What Causes Numbness In Right Leg?

Hello. I m just curious if I should be concerned or more active..until now. Long story short, I have always been active. very involved with yoga and the gym. I recently haven t been going to the gym since I got my new job. Which is a behind the desk job, resulting in me sitting down for 8 constant hours a day, getting up to make a copy, get coffee, take a restroom break, etc. For about 3 weeks now my right leg has been starting to go to sleep more frequently then usually. So I get up, make a lap and try to walk it off. It has caused me to lose motivation for the gym, therefor my muscles aren t being worked hardly at all compared to a 5 days a week gym goer. My leg is constantly numb.. Is this because I haven t been as active and my muscles are tighting up or do I have a pinched nerve? I have mild to no pain right now. I m worried about it getting worse in time if I don t get it figured out