You most definitely need to see your doctor.
It could also be one of your Bartholin glands... sounds a lot like something I went through a few years ago. The GYN drained it, it healed, and all was well.
Have you been checked for BV (bacterial vaginosis)? It's pretty common, and should be treated with antibiotics if you have it. Other possibilities might be allergy to latex if you use condoms, (though why it wouldn't be generally throughout your vagina if that is it, I wouldn't know), STDs, or other kinds of infections. Definitely time to see your doc. If it is BV, your hubby should be treated at the same time, because he can pass it back to you once you are healed. Good luck!