What is wrong with my legs ?

ever since i was 3( my mom said i used to wake up screaming because my legs hurt so bad she tried rubbing/maging them but it didn't help anything) i have been having this aching in my legs below my knee in the muscles i am 13 now and i am still having them it happens when i am standing up and sitting down and i don't go out and run or anything but i play at recess and P.E but not as much to get sore.My mom has MS is that a genetic thing ? what should i do ? should i see a doctor ? please help it hurts and i can't handle it anymore.