I am female, 36 yrs. Since last 2 months just when the periods start, I have intense pain in middle lower abdomen. Last month when I visited doctor, she advised for a USG(Pelvis). Got it done, but nothing was found. The pain went off in 5 days last month. This month again, when my periods started, the same pain re-occurred. But this time the pain did not go off. Went to the same doctor and she has again asked for a USG(Pelvis). It makes no sense to me to take the same test when the result came negative once. My question is if USG doesn't show any result, what is the next step of test to find out the pain.