Hello, 8 weeks really is very "early days" in recovery from major surgery. It is definitely not unusual to have symptoms while you are healing, and pain from sitting or lying in one position is fairly common. Remember that, in addition to bone and skin healing, all the muscles, ligaments, tendons and nerves must heal too.
In my experience, even though annoying, it is actually a good thing that your body is "reminding" you - through pain - to get up and move frequently. After one of my hip surgeries, it was almost 6 months before I could sit for any length of time - my coworkers laughed at me - but our meetings got a lot shorter!
If it gets worse, or standing u and walking doesn't relieve the pain, you may want to contact your surgeon.
How is your recovery going otherwise?
Sue

I experienced that mostly while in a car, 30 min before it was intolerable. I would pull over, stretch, elevate/ice, then be able to resume. It took 5 months, after that wasn't a problem. Keep positive.