pins and needles [uncountable]
an uncomfortable feeling, often in your foot or your leg, which you get especially when you have not moved part of your body for a long time, and the supply of blood has stopped flowing properly:
I'll have to move because I'm starting to get pins and needles in my foot.
2 American English
to be very nervous and unable to relax, especially because you are waiting for something important [= be on tenterhooks]