I'm 19 and have severe pain on lower right side of abdomen. Also have missed 3 periods. Drs thought it was my gallbladder so they removed it now 2 weeks later and the pain is back. I take bipolar meds and also have a benign mass on my liver which the drs said is not causing the pain. When I have the pain I am very nauseous and tend to vomit. What could the pain be? Please help? Should I be worried? Also took 2 pregnancy test all came out negative and has multiple urine and blood test done in hospital and nothing has shown up.