How to go about fertility check up

It’s been 4 years of ttc and I’m only 22 with no luck. No miscarriage. No pregnancy. Nothing. I’ve tried tracking cm-temp- symptoms-ovulation test- tracking cycles. So I decided I’m going to use some tax return for a check up. I had a pap a little over 6 months ago and all was normal. So do I go to a obgy again or a regular dr ? Can an obgyn do bloodwork on me ? I don’t have insurance either.