I think my throat pain makes me think about euthanasia
Are you serious? Have you seen a doctor?
I have the feeling that medical doctors simply don't help me
If the pain is that severe and the doctors aren't helping, you should get a new doctor!  Keep trying to find the right medical help to get it treated!
I'm certain that medical doctors can't help me and euthanasia is the only way out.
That's a serious overreaction to some throat pain!  I'm equally sure that if you talk to other doctors I'm sure they'll be able to find some way to help you.  Suicide should never be a solution to your problems!