I've had a pea sized lump inside my cheek in the middle between the two sets of teeth have had it for yeats?

Don't worrry: It's probably from biting your cheeks, or a swelling from a salivary duct. If it gets bigger, changes color, or becomes sore, see an oral surgeon right away.

Stensens duct?: Hard to tell without more description, but are you possibly referring to the tissue in your cheek that is nearer to your maxillary first - second molar area? This is the stensens duct, also known as the parotid duct which drains saliva from the parotid gland. Is it present on both cheeks? If it's only on one cheek, then it's not likely your duct but something else. Send more details. Good luck!