I have a swollen lump under my left ear/start or my jaw it's about the size of a grape it's grew the past few weeks and became rather sore and sensitive on the lump and all over my left side of my neck down to my collar bone is it serious?

Blocked gland? A sebaceous cyst is a collection of oily fluid that occurs when an oil gland is blocked. Some folks are more prone to them than other and they often appear on the neck, shoulders, and back. Try to avoid skin products that are oily. Stay away from transfats and bad oils, which is good for overall health. See doc for proper diagnosis because it could be more serious.