I noticed a small lump in the back of my throat right behind my tonsil that causes pain when I swallow. The limp is a light orange red color. Cancer?

Most likely benign. Although cancer is possible, it would be very rare in your age group. This is most likely inflammation from a recent upper respiratory infection or allergy. Nevertheless, if this does not resolve in a few days, ask your doctor to look at it.
Very unlikely. Go see your doctor for an exam. Tonsil cancers are generally painless, often difficult to see by eye, and begin appearing usually in the 30s in non-smokers.