I have a firm mobile mass just behind the ear lobe since 1.5 years with no systemic symptoms,size fluctuates n sometimes overlyin skin is warm n red

? sebaceous cyst?: You should have your PCP or a dermatologist look at this.... it may be a lymph node, or it may be a gland in the skin that gets inflamed and infected on and off (a sebaceous cyst). Your parotid gland is IN FRONT of your ear, so I doubt it is a problem with that. But having a doctor examine it is your best course of action. They will probably want to biopsy it or excise it.

Enlarged lymph node: See your PCP. Direct clinical examination is warranted and essential to exclude any other causes.