I am 28 weeks pregnant and have had this pain on my right lower side of stomach what could it be?

I am 28 weeks pregnant and have had this pain on my right lower side of my stomach. It hurts more when I have to go to the bathroom (number 1). It hurts when rolling over in bed and when I have to lift my right leg to get dressed or in and out of car. Could it be round ligament pain or something else? I already had test for possible UTI and urinalysis was nornal?? I also see doc next week and will ask him. This has been going on for about a month now...