Male, 23. all of symptoms of acute prostatitis, no diagnosis. taking doxycycline hyclate. should this help clear it?

Maybe, maybe not: True prostatitis is rare at your age (23), and when it occurs, it's usually non-bacterial (often not due to any infection at all), and doxycycline and other antibiotics don't help. It may be worth a try, but don't get your hopes up too high. Typical symptoms (testiular or low abdominal pain, urinary discomfort, etc) often are the chronic pelvic pain syndrome. Google it for for more information.