When a new client comes to me and asks why his lower back hurts, I go right to exercises that require strength and activation of the core, glutes and hamstrings.
Almost always, I can tell right away that two of the three are weak or underactive. Oftentimes, it's all three. That's why his back hurts.
When a client reports that her shoulder hurts, I immediately begin exploring their posture and upper back strength. Almost always, I can tell right away that her upper back is weak, and the situation has gotten worse from all the time she spends sitting hunched over a computer. Her shoulders hurt because they're being asked to do things they're not supposed to do in order to compensate for muscles that aren't doing their jobs.
WHEN TO SEE A SPECIALIST
Of course, there are certainly times when I can't quite put my finger on what exactly is causing pain. That's what orthopedic doctors and physical therapists are for, and I have a short list of both to whom I refer clients when I can't help them.
Those instances are rare, though.
In almost every case, a person with joint pain can find relief and improvement from a well-designed exercise program. Avoiding strength training is only going to make the problem worse.
THE REAL REASON YOU HURT
Pain is often a response to weakness. Tightness is often a response to weakness. Getting stronger will improve both.
The answer to a better, longer and better quality life is to get stronger and more active, not weaker and less active.
If you're dealing with nagging pain and you've been avoiding the gym because of it, that avoidance might be the very thing making it worse. A smart, well-designed program that targets the right muscle groups can change everything.