I had lap. Inguinal hernia surgery three weeks ago. I feel a "pulling sensation" near my right scrotum. How do I cure this? Can I start working out?

Hernia repair. Check with your doctor, you may have nothing to worry about. He can give you instructions as to when you can workout.
Give it time. Not unusual to have pulling sensation this soon after surgery. Some of these symptoms can last for up to three months. As for exercise you should check with your surgeon. However, laparoscopic procedure allows you to return to exercise much faster than conventional surgical repair. Professional athletes (who have to work out) return to full exercise regimen in 2 to 3 weeks.
Normal . There are a variety of different sensations similar to yours after most operations. This will pass in time, but you may have it or some other sensation forever. These should be minor and not limiting. It should also be fine to return to normal activities including the gym as tolerated by pain. Check with your surgeon of you have any doubts.