There are many reasons a massage therapist would work somewhere other than exactly on top of your most painful spot. If we drill down through all the details though, the real reason is: It depends. But since "it depends" is not a very satisfying answer, here are the top 5 reasons I might not be working directly on your sore spot.
Note: There's some overlap between some of them, but that's unavoidable. Nothing exists in a vacuum. That's physiology. That's life.
1. Your painful spot it too painful to actually touch
This may seem obvious, but it's not always. After yelping in pain, some people continue to ask me to go back the same spot over and over. But here's the thing, you'll actually get better results from your massage or bodywork session if you're not in pain during the majority of it.
If the slightest touch causes you to flinch in pain, powering through it is a great way to guarantee that you'll have a ton of soreness for the next few days. It's best to start at the periphery of the pain and work our way in. By taking this approach, we save you a boatload of pain. By the time we work our way in to the original "hot spot," it should tolerate the work it needs fairly comfortably and respond quicker. By working this way, you may only need 5-10 minutes of work on a spot that's merely uncomfortable instead of spending the better part of the hour writhing in pain. Bonus: You should be left with very little, if any, post massage soreness.
2. Your painful spot is pushing back against the therapist's hands as they work
It might not be too painful for you to tolerate, but a muscle that feels threatened will contract to protect itself. To a therapist's hands it often feels like the muscle is pushing back. When that's the case, we need to back off on our pressure until it doesn't push back.
There are many reasons a muscle could have this protective response and I won't bore you with them all. Sometimes it's pretty easy to tell why. Maybe there's an injury or the muscle is being smushed or stretched too much.
Sometimes it's less obvious. Perhaps another muscle is contracted tight and creating a line of force that's causing the muscle to be stretched farther than it's comfortable with. The result is a muscle that feels threatened constantly.
No matter the reason, if the muscle's pushing back we've got to back off that muscle and find ways to make it feel less threatened. This might mean less pressure, finding the closest spot that doesn't have a protective response, or working other areas of the body altogether.
3. The nervous system needs to calm down
Lots of things cause the nervous system to be in fight or flight mode (or more prone to it than usual). The biggest culprits are physical, mental, and emotional stresses. These stressors can be obvious things like hating your job, being in pain, or having too many things on your schedule. They can also be hidden things like that thing that used to stress you out, but you got used to. (Spoiler alert: The only thing you got used to was the feeling of the stress response.) If you've had pain or stress for a long period of time, the nervous system can become hypersensitive and prone to over-reacting. This isn't a malfunction, it's a safety feature, albeit a sometimes annoying one.
By calming your nervous system in general, we turn down your fight or flight response . This in turn causes your relaxation response (aka rest and digest mode) to ramp up which makes massage and bodywork much more effective.
4. The painful area is a actually a compensation for another issue
There are times when an area begins to hurt after it's been compensating for something. It might be compensating for an injury, painful or constricting clothing, some postural habit, a movement habit, or the crap ton of stress you've been under. If we don't address the original reason for your pain it'll keep coming back.
As an example, if your hip hurts because you were walking funny after you twisted your ankle, you'll likely need work on both your ankle and hip as well as the joint between those two, the knee. If you regularly wear a compression garment, such as shapewear or a binder, you may only have pain in front (or back or side) but the entire area that was compressed needs to be worked if you want to have less pain for a longer period of time.
5. The spot that hurts is not the spot that's causing the pain
It's incredibly common for one set of muscles to cause another set constant, or near constant, pain. In a nutshell, here's why: the ends of each muscle attach to one of your bones and more than one muscle attach at the same or nearby points. This usually involves working the opposite side of the body to where the pain is: front/back, upper/lower, right/left. The two most common incidents of this involve low back pain and pain between the shoulder blades.
This is what happens when your back spasms when you move from a sitting to a standing position. Let me explain. If the muscle that helps you sit (flexes your hips) is too tense, when you try to stand it'll pull on the vertebrae it's attached to which, in turn, pulls on the low back muscle that's attached to the same area of the vertebrae. This causes the low back muscle to get over-stretched, which causes it to contract to protect itself. That protective contraction is the spasm you feel.
This is also what happens when you have a (near) constant pain between your shoulder blades. To understand this, you need to know a few things to know about the shoulder blade and shoulder joint:
Part of the shoulder blade is the socket part of the ball and socket joint known as the shoulder. So, whatever happens to the shoulder, happens to the shoulder blade.
The shoulder is the most complex joint in the entire body, which means it has more muscles/tendons and ligaments attached to it and running though it than any other.
The arm is the second half of the shoulder joint. Any muscle affecting it, affects its relationship to the shoulder and, therefore, the shoulder blade
Muscles from the chest, upper abdomen, shoulder blade, lower back, and neck attach to one part of the shoulder complex and affect all the other parts of it.
Excess tension in any of the muscles attaching to any part of the shoulder joint can cause pain somewhere else, and the place that pain is felt most often is between the shoulder blades.
Whether it's your low back or between your shoulder blades that hurts, don't be surprised if we need to address at least one area on the opposite side of the body.
Putting it all together
There are many reasons that a massage therapist like me will not work directly on your sore spot, at least not right away. I can't speak for other therapists but I always try to let you know when and why I'll be doing that. If I'm particularly human one day and forget, feel free to ask.