I was diagnosed with acute prostatitis given levofloaxcin which immediately helps no symptoms since. i feel like my left testicle is bigger or swollen ultrasound revealed no tumors so can prostatitis be the cause? i read it could not sure how true?

The prostate is different from the testicles, however bacteria infection could affect both of them. You should follow up with the provider and possibly you did not take the antibiotics for long enough or levofloxacin is not the appropriate antibiotics for what could be causing the infection. A second opinion is also an option and I hope they examined you and took cultures before the levofloxacin.

Ultrasound should confirm or deny your feeling of 'enlargement' and not just 'no tumors'. If it was enlarged the report would have stated it as would a clinical exam by the ordering doc. A swelling (epididymo-orchitis) can occur as a complication but it is a painful swelling and gradually resolves with treatment. If still in doubt about the enlargement pl see a Urologist.