50 days post FUT of about 8k hair. Now I have pinching feeling on the recipient areas. Is that normal?

Not sure how many grafts you had done or how wide your incision was but 8000 hairs seems like a lot so I imagine a pretty aggressive surgery.   It is common in strip surgery to have some nerve involvement from the incision that can cause numbness and tingling for unto a year.  In terms of the recipient area, this is less common.   The good news is that most peripheral nerves (that is the small nerves in your scalp) tend to heal over time and the numbness and tingling you are feeling now can generally indicate that the healing is happening.  

I noted that you said you got 8000 hairs not 8000 grafts, quite a difference. IF you are having pain or discomfort, go back and see your surgeon