Hello doctor I am experiencing cracking of joint in my chest and a little upper back pain. Upper back pain is not an issue for me but the chest joint cracking at times scares me a lot. It first started as a little pain in my left upper chest some days later it started to crack and from then when ever it pains I feel like stretching and when I stretch in a certain way it cracks with a knuckle cracking sound. And when it cracks the pain goes away and comes back later and I stretch again. The pain and cracking happens only in the second left rib is what I feel (towards sternum) I carry 20L water bottle to the 3rd floor every alternate day from the past one year can it be caused because of that? Thank you.