I have felt a pea size knot on he top of my head it does not hurt should i be worried?

See below: It is hard to say what it is without examing you. The best thing is to have it examined especially if it persists or bothers you.

Possible cyst: While one cannot say for sure that this is a cyst on your scalp it is certainly possible. You should see a dermatologist to see if this is the correct diagnosis.

Trichilemmal Cyst: Trichilemmal or pilar cysts are common intradermal or subcutaneous cysts, occurring in 5-10% of the population. Greater than 90% occur on the scalp, where trichilemmal cysts are the most common cutaneous cyst.Trichilemmal cysts are almost always benign. They may be sporadic or they may be autosomal dominantly inherited. Treatment is surgical excision.

No: It is most likely a harmless cyst, but i would suggest confirming with a dermatologist.

Could be pilar cyst: A firm, round lump on the scalp that does not go away could be a pilar cyst. Pilar cysts are not dangerous, tend to be multiple, and tend to occur in multiple family members. See your dermatologist for accurate diagnosis and removal, if necessary.

Could be anything: It could be scar tissue, cyst, or possibly a type of skin cancer. It would be difficult to say without looking at it. Since it is in a location that is difficult for you to monitor i would have it checked by your primary care doctor and consider having it removed.