Yes, the person was correct. If you had current, infectious syphilis that needed treatment, your RPR would be reactive. The tests that are reactive might always be reactive in people who've had syphilis that has been successfully treated in the past.
Constant headaches can be from so many things, but you should talk to your doctor about that. When you were tested for syphilis, were you tested for anything else? Constant urination can also be caused by a lot of things - urinary tract infections, STDs, prostate issues, etc.
Definitely work with your doctor on this. If you haven't tested for other STDs, like gonorrhea and chlamydia, you should do that, and check for a UTI, too.
Good luck, and let us know what happens.