Pain after peeing

so recently I’ve been having this stinging feeling inside my vagina after I pee. It’s weird bc when I pee it feels normal & the stinging sensation doesn’t come until about 5 minutes after I’m done peeing & it takes like 15 mins for it to go away. I dunno what it could be. I don’t have any foul scent coming from down there or from my urine. my discharge is just solid white & a little thick but not like cottage cheese. I also tend to hold in my pee a lot & find the pain comes when I’ve held in my bladder for a while.

Do you guys have any idea what it could be? I’m afraid it might be an STD so I did plan to get a test ASAP.