What Causes Discomfort In The Lower Abdomen On The Right Side?

Hi, i ve been experiencing some lower abdominal discomfort, particularly around my right ovary - i would say for the past week or so. As i have just had a monthly cycle i put this down to the usual pains that could come with that, however this month my cycle only lasted one and a half days which isn t normal for me. I have taken a pregnancy test to rule this out, and although my cycle has now ended i am still experiencing the discomforting pains to the point where, for the past couple of nights i have been woken up during sleep from the pain and have to lie on my back in order for the pain to ease?