i got that popping shoulder thing too. it started when i took a bad fall and arched my body when i hit the wall. the shoulder didn't even hurt, but the exercises that i had been doing before caused the shoulder to pop, but not hurt.

long story short, the popping led to pain - bursitis (the bursa twice normal size), tendonitis. this is 5-6 yrs later, and light at the end of the tunnel. it is finally starting to get better, and i can actually do some of those old exercises now without the popping. some still make it pop, and the doc says don't make it pop if i can help it.

sometimes things do heal with time, and if u r old like me it takes a lot of it.