What Causes Recurring Lump Under The Chin?

I have had this for a while. There is a lump on my neck area. It is on the left side between the chin and jawline and on the bottom of the chin part. It comes and goes randomly and it stays about the same size (1 in, not exact) every time it comes back. I can move it. It is sore if you push it in but if you move it, the lump itself doesn t hurt when you squish . It is hard-ish, though im not sure. But after a week or two, at times, in less time, the lump goes away completely. And there is no sign of pain anywhere. I do get canker sores often inside my mouth, but I m not sure if it is correlated to the neck lump. The canker sores reoccur around once every month or two but never stay for an alarming amount of time . This has been something that comes and goes for over a year now and I am never sure whether or not I should get a doctor to check it out! Please give me advice!