How Is Pain In Thighs Healed?

The front of my thighs have been aching. It feels muscular, yet, is not affected by movement or exercise. It sometimes feels worse at night also bothering my right knee and hip. I also noticed that it is worse when I sit for long periods of time. What type of doctor should I see for this? It has been happening on and off for a while now, but I'm noticing that it is becoming more and more frequent.