This is inflamation or something else, from 4 year and no pain.

That's a long time: Four years is a long time, and usually no pain does not always indicate that there no inflammation present. There are other signs like redness, and swelling that would indicate inflammation. So, it's best to see your doctor to have it physically examined, so that you get the proper diagnosis and treatment done., four years is a long time to wait, so don't delay any further.