I have 1 red spot on the roof of my mouth, its really sore, when i swallow it hurts, and a lot of people i know are smokers, what can this be?

Possibly and ulcer: You may have an ulcer. Any break in the lining of the digestive tract exposes the underlying layers of the digestive tract. If it is not gone in 10-14 days you should get it looked at by a physician or dentist.

Many things: This could be several things from a lesion, salivary gland issue to an infection. Have a dentist evaluate you. Yes smoking is a risk factor for oral cancer. Please see your dentist.

Hard to say: There is no way to diagnose a clincal lesion over the internet. Please seek the help of a local dentist. Your lesion could be anything from a canker sore, to an oral abcess, to an abrasion, to oral cancer, or something else. The sooner that you are seen the better.. Take care...