Weighted Chin up injury?

[Trent Whalin]

I wasn't sure where to put this but I thought I'd ask you fellows. About a month and a half ago (now closer to two months I think), I was in a rush and did some weighted chin ups right after I ate to go to work. What I mistake. I felt like I had pinched a nerve or something right under my sternum, left side. I thought it was heartburn, but it wasn't. For the next week, It was uncomfortable to breathe like my rib cage was super sore. After that it is like it virutually cleared up. I still had the occasional twinge. This twinge reaggravated at work on Mondays when I had to unload the truck (most boxes are not that heavy if at all) and there were heavy stuff like those stupid clay pots. It slowly went away but, last week I decided to do some push ups. This twinge (as opposed to the sore breathing of the first week) returned. Some times it is in lower part of my sternum, sometimes upper. It is felt more when I tense like my pectorals sometimes though sometimes I do things and it feels weird, I do them again and nothing. I have been burping a lot more tooo....any thoughts?