Hi i have a lump in side if my cheek near my back teeth and its a bit tender, what could this be? i don't know whether it's from biting my cheek

Possible trauma: This could be trauma from accidentally biting the inside of your cheek while chewing or depending on the location, the parotid gland duct which is located around the upper back teeth could be inflamed for some reason. If it doesn't clear up after three to five days you should have it checked by a dentist or an oral surgeon.

Could be biting: That area of your mouth is prone to trauma, especially if you have your wisdom teeth.. There is not alot of room back there. It's best to consult with your dentist who can evaluate your situation and advise you of your treatment options.

See your Dentist: It could be an infection, inflammation from irritation or trauma, tender salivary gland or lymph node or something else. I recommend that you see your dentist as soon as possible to try to determine its cause rather than just wait and see if it goes away. Although it might be nothing at all, is it worth taking a chance that it is more serious?