This could be an infection in your urethra, prostatitis, a urinary tract infection, maybe even dehydration.
You really need to see a doctor for some testing and a digital rectal exam. It sounds like you're really busy, but you need to make some time for this. You don't mention what your sexual risks are, but it could also be an STD, like chlamydia, gonorrhea or NGU.
Don't put this off too long. An untreated infection will only get worse.
And thanks for what you're doing. You're helping a lot of people.