My top left teeth are sore throbbing and aching after I eat or drink. I have recently had a sinus infection and still may have it. Not sure if that has anything to do with this. I also may grind my teeth at night. Wondering why this is and if it is something bad

I suggest you go see your dentist. Sounds like there is a LOT of infection going on there, especially as you think you have a chronic sinus infection.