I have the same problem but its chronic,it would guess you also have a case of sciatica,when I have a flair up(which is often these days) I use heat therapy and rest.Sometimes I'm on the heating pad for days!Your Dr. can prescribe prednisone for you which will help with the inflamation of the nerve.
Sounds like it could be sciatica. But I don't know about sitting and lying down being uncomfortable. Try Aleve (with food) for a few days and see it that helps. Usually, Sciatica goes away with time. If that doesn't help try to see a physician. Could be the hip. Did you do anything to injure it?