Please check with your gynecologist. There isn't much he or she hasn't heard. Why suffer trying to figure it out on your own?
Also been with my partner for six years, at first thought it was normal until he mentioned it too.
Also avoid spermicide, tends to chafe both yours and his.
I get a similar issue after sex. Usually it indicates youve been too rough or that you havent climaxed.
This sounds silly but if your lady bits were recently shaved or waxed that does effect that whole area. Lotion meant for your bits and a cold towel there usually help. Also feminine wipes help. Avoid cleaning up with tp or tissues, that usually causes morr irritation than necessary.
Also try cutting out special lubes, ie his and hers by Trojan, use a simple water based lube only. If you use condoms you could have developed a sensitivity to the latex. Happened to me a few years ago, switched/removed condom better for my lady parts.