Recurring swollen Gland under jaw, I have a cracked wisdom tooth on the same site could that be causing the swollen gland swelling round tooth aswel?

Possibly. cracked tooth may mean the inside of the tooth is infected - infections can lead to swelling of local galnds.
Sure. Are you waiting for the unrestorable wisdom tooth to cause a major infection? Your body is telling you something is amiss.. seek the care of an oral surgeon immediately and avoid a tremendous amount of swelling and pain. The tooth needs to come out.