I've been having abdominal pain and leg pain on my right leg for about one week. the leg pain gets worse at night. i also have been constipated for 3 weeks. was using a laxative weight loss pill.

Two separate problem: The pain started before or after taking the laxative? I don't think that the abdominal pain necessarily has some relationship to the leg pain. Have you been passing gas during the last 3 weeks that you have been constipated? If not, then a medical ileus needs to be considered and you should run to your nearest hospital. If not treated you could end up with a perforation. Not sure of leg pain.