I suffer from a back injury compression fracture and chronic pain. my left foot felt swollen tonight in past cold and numb a little why? what do i do?

Compression fracture: Often when there is some nerve impingement there is a feeling of swelling. The numbness also signals possible nerve root impingement. I do not know what level your compression fracture is or the percent compressed. I would seek the attention of a neurosurgeon for evaluation and possible treatment.

See a doctor: You did not mention where is your compression fracture, what is the cause and has there been a recent imaging study. The concern is there may be some form of compression wither at the cord or at the nerve root level. See your doctor and possibly be evaluated by a neurologist and possibly by a spine surgeon.