Joints click/crack get louder with more exercise and gets more painful. What could it be?

So about 4 or 5 years ago I was training for baseball season trying to pack on some extra pounds of muscle and it worked but the problem was I had no idea what I was doing. I ended up with chronic tendonitis which for the most part has now gone away. My issue now is when I start to do any kind of lifting my joints start to click/crack. It starts off not to painful and pretty quite but by the end of a set it continues to get louder creating real bad pain. The more often I go the worse it gets to the point where it is no longer tolerable; after my joints ache for quite some time. Anyone have any ideas as to what this may be? It has made life a lot more difficult limiting jobs that I can work, and I haven’t played sports since the injury happened. I have seen doctor after doctor, had MRI’s and x-rays and they say that there’s nothing wrong and that the clicking shouldn’t hurt. Problem is it does. It’s in both shoulders, elbows and knees. Anyone every experienced anything like this? At this point I really don’t know what to do and have pretty much given up trying to figure out other ways. I cant afford treatment anymore and have spent 1000’s in the last couple years trying to get this all sorted out. Thanks in advance for all answers.