I had a septate hymen. Tampons hurt a lot but were still manageable. Sex hurt the first time (stinging feeling like you describe, both during and for a few days after) but was fine thereafter. Use lots of lube, do plenty of foreplay and accept that there's going to be pain but it will be brief. If you are still struggling despite trying this, do see your GP, of course, but be aware you will probably have to wait for a very long time to see a specialist. Good luck.