Pain in both sides of rib cage mid way through sleep

I experience pain in the sides of the rib cage after a few hours when I fall asleep.. at times it has been very terrible and I tried moving, changing positions but it won't let down. Finally I have to get out of bed and maybe half an hour later it goes away... i don't experience it when I am awake during the day... just happens when I sleep, be it afternoons during the weekend... I went to the doc a few times but she too could not know what's going on... she prescribed me some medicines like Ibuprofen and antacids but they didn't help too much and I discontinued them because I don't want to be taking them when they don't really help... I have seen similar post on this site and quite a few people experiencing the same problem but I couldn't find anyone providing a concrete reason or cause or remedy to this problem... I too thought it might be due to bed.. so i experimented sleeping on the sofa and even directly on the carpet floor... it too didn't help much as the pain occurs in the middle of the sleep... The doc did some tests like chest x-ray, urine sample, blood test but they were all normal... sometimes i do have erratic bowel movements and gases and these days I feel like I need to drink more water to just to get that burp... please share if you had similar experience and how it was diagnosed.