Neck Tightness on Squats for Reps

Today I did 315x8 on oly squats, which was a PR, but at the end I fealt a huge amount of pressure around my ears and both sides of my neck fealt very tight, kind of like when you sleep wrong except on both sides. It probably has something to do with my bar placement and lack of oxygen, but has anyone experienced this? Do I just have to get used to it or is there some prehab work i can do to help this? Maybe I should train my neck/traps more?

Traps pumped from holding the weight up.