Look up tonsilloliths, or tonsil stones. I've had them on both sides for years because the doc never would remove my tonsils as a child. They cause bad breath and usually get tender and swell the lymph node under my chin with upper respiratory infections. Some people can remove their stones with Q tips but I think mine are internal or healed over and I cannot do this. The ENT will have to do that for me. It is caused by bacteria getting stuck in the crypts of the tonsils and forming infections which, after long periods of time calcify and become hard. They are seen on CT scans of the neck. Mine were anyway. Hope this helps.
I've never heard of a chronic swollen tonsil as being associated with cancer, but I'm not a doctor. Have you had any other symptoms besides the swelling? Sometimes lymph nodes will stay enlarged and never go back down after going through an infection, so possibly that is what your lymph node is doing, as for your tonsil I have no answers. It's probably a good idea to see the ENT doctor, but try not to get too worried about it just yet.