Head pulses then anxiety rush

Hi there,I'm 46 yr old male.Have been a smoker(casual,less than 10cigs a day) for approximately 15-20 yrs.Quit last year in June,cold turkey! after learning that a close friend was diagnosed with a brain tumour.During these last 6 months,been having mild pulsing top left of head followed by feeling of anxiety rushing to my stomach.This pulsing does not hurt,comes at random times and I don't really notice when I'm working(Autobody)My friend past on in Dec. After this,I became more paranoid and have gone to the doctor for a physical.Told the doc about my "pulsing" and about my friend.He says more than likely stress related and especially after the experience regarding my friend.I'm self employed,care for my mother,and a young family.So I do have a lot of daily stress.Blood test results are good,x-rays of lungs ok,physical is good.Doc says "You do not have a tumour" I asked about a MRI and he says he needs a good reason.I just want some re-assurance.Doc says try to take time to relax,excercise,eat and sleep properly.Come back to see him if my head pulsing and anxiety persists.No meds given.What is your opinion? Thanks in advance!