Hi, I am sorry you are having these issues. Have you asked a dermatologist about this? They sound a little bit like Shingles, they can hurt at times, these can come after a person has had chicken pox.
a pain where the scratches are ? could be stretch marks if you are overweight
No they don't itches but sometimes like ones a week a great pain happens for 15-25 secs
Are they itchy it could be hives, dermagraphism, do you scratch them ?