13 year old with bumps on back of the neck..harmful?

Im 13.In the middle of janurary i found a bump on the back of my collar.It was undemanding to feel..smaller than dime...not easy..didntmove.Its gotten alot smaller since than its about the size of a pencil eraser.softer too.Moves somewhat more than before.in good health about a month ago I found another one like peas in a pod thing except a bit bigger than before.Im scard,My parents said its probably nought.They both seem to be getting small but im terribly scard that it could be cancer.Im not a health freak but cancer have always scard me.they are both astern my right ear.they dotn hrt at all.my collar is soem times tingly and hurt but at school i hold nothign to support it and i si weird my nouns has hurt mywhole existence so..
Answers:

thyroid..?

i got a couple of them on the fund of my neck to but my mum say its probably i swolen spot and that she used to get them adjectives the time and my sister she she got them too but they other went away.

Why hold my periods stopped?

Get it checked out, dont swing around on flippin womenanswers.org

Peeing outdoors?

It is most likely a carilage deposit. Your ear is completely made up of cartilage so it could be that. Go to the doctor or form clinic to be sure though. Good Luck!

birth control pills?

I don't think it's anything, but I'm not a doctor. I've have a similar bump on my ear lobe that kept appearing and disappearing depending on the weather. It can be thousands of harmless things, close to a mole, pimple, or something. At the same time, it never hurts to be in motion to the doctor for a general check up next to some questions.