The painless lump that you are having seems like a sebaceous cyst. A sebaceous cyst is a closed sac occurring just under the skin which contains a "pasty" or "cheesy" looking substance called keratin.They may occur anywhere on body but scalp, ears, back, face, and upper arm, are common sites for sebaceous cysts. Blocked sebaceous glands, swollen hair follicles and excessive testosterone production will cause such cysts.
Generally no treatment is required but they become painful then it means they are infected,Then surgical excision by traditional wide excision, minimal excision, and punch biopsy excision may be required.
The other possibility is of swollen lymph node.It may be due to some recent infection.
Hope it helps.Take care and pls do kee me posted in case you want any more clarification.Kind regards.
My daughter gets lumps like the one you described. Sometimes w/headaches, other times w/ no pain. Hers is usually on the right side of the back of her neck, close to her hairline at the base of her skull. On each side of the back of your neck there is a tendon, thats where hers would appear.
When our family doctor first looked at it, he said he could drain it in a minor surgery. She was 14 yrs. old then and what he said freaked her out. So we got a second opinion from another doctor who sent her to a Physical Therapist. He put a heat pack on her neck for 20 minutes, then had her lay on a table on her back. Standing behind her head, he cupped her neck in his hands and with slow but steady pressure just using his fingers massaged her neck, from her shoulders to the base of her skull. She was falling asleep. When he got done the swelling was completely gone. It was a muscle spasm, and sometimes they get real hard and round, go away and can come back in the same place or a different area.
He told her she could us a Tablespoon, (back side of it) heated in hot water applied to the swelling next time or cold ice pack or massage again . Different things help different people. She takes a hot shower now and that helps. If it gets real bad and causes a headache she takes an Advil. She is now 29, and still gets these. Sometimes from tension, stress, with a headache or just pulling a muscle, lifting laundry or her 3 year old, straining your neck at a computer can cause it if your there to long. Lying on your stomach watching tv with your chin propped on your hands can be a sure way.
I hope between my explanation and the one above from kindd, that your more at ease until you see the doctor and maybe it will be gone in two weeks. Keep us posted
P.S. Quit Poking It! LOL