I did excess dance for the past 2 days, do u think my discomfort on left side under ribs has to do with that? scared of it being lung, spleen, gb, etc.

Lots of dancing: Can cause residual strain of muscles you normally never use in this way for 2 days. However, you have a history of gerd, heartburn and acid reflux. So, that could have aggravated this condition, if you weren't well hydrated while dancing for 2 days. So, best to have it examined by your pcp, and see what s/he finds when palpating area. You'll have your answer soon enough!

Yes, likely strain: More than likely, the physical exertion during your dancing resulted in musculoskeletal strain. Assuming that you did not dramatically fall or hit something, it is unlikely there is any internal injuries associated with this physical exertion. Some analgesia, such as Ibuprofen or even tylenol, (acetaminophen) will help with the pain, which should subside over the next few days.