Red and swollen tongue, with lots of pain. no meds, no different foods, no changes that couldve brought this. could it be caused by thrush?

Small chance: Usually with thrush though the distinguishing factor is a white wipe-able coating from the tongue or other areas of the mouth. And usually it doesn't affect a healthy individual unless oral hygiene is really poor and/or the person is under a lot of stress. There are lots of reasons for a swollen red tongue. Get it examined as soon as possible.

See PCP: Possible. Best way to determine is to see physician to examine you and do testing.