Odd feeling in the tip of my urethra

It's been a couple of days and all day I have this weird sensation in the urethra at just the tip of my dick. It's not painful at all, actually almost like, stimulating? But it's very annoying. I've been drinking lots of water and peeing just fine, no burning sensation, no other changes and I only have one partner so i doubt it's std.

It started happening after I ejaculated 7 times in like half a day. Google told me it might be leftover semen that's irritating the urethra but it's been days now. It is a constant feeling and it's getting very annoying and I'm frankly getting a bit scared.

Also it sort of gets better when I'm sitting down? It's at its worst when I'm standing up. Anyone else ever had this?