Scared about my health.

I need help with figuring this out, so I have a few problems. The first thing is every time I move don't matter if I'm sitting up, laying down, stretching, etc my bones always pop. Mainly my elbows and knee's. My shoulders sometimes pop to. What does this mean? I can't control it. I have been also experiencing pains in the middle of both my arms ( cubital fossa ) I think I

it's called, they are really sore. Can anyone explain why? Also every time I lay down my chest hurts, like if I lay on one side I get a sharp pain and it's the same on the other side. For the pain to go away I have to either lay flat on my back or chest. It's weird to me and I have no clue why all this is happening. Just to give you a background I will say that I don't exercise a lot, I weigh about 149 pounds , I'm about 5'9 , and my daily activities include working and some school activities. I do eat a lot, I have a high metabolism and I barely gain weight. Could my eating habits and lack of exercise be the problem?

Please help.