Sudden high PSA and MRI Results

Hello,
I am 51. For the past few years my PSA has fluctuated between 2.5 and 3.5.
On 14-March-24 it was 4.4. So got retested thrice. On 22-March-24 it was 3.09. On 5-April-24 it is 17.5. On 6th April it is 16.5
Any idea what is happening ? Uro Oncologist thinks Prostatitis. Suggests another PSA after 1 month and MRI after 6 months. Should I wait that long or just ask for biopsy.

MP MRI was done on 6th April. Report below:

Peripheral Zone:
There is mild to moderate diffuse T2 hypointensity involving the base mid and apical region except for far lateral areas in the mid prostate. There is no significant restricted diffusion. There is symmetrical enhancement on post contrast evaluation. PIRADS 3

Neurovascular bundle: Unremarkable
Seminal Vesicle: Unremarkable
Prostatic capsule: Mild irregularity on the left side
Transition Zone:
Pseudo capsule and differentiation with peripheral zone is preserved. Mildly enlarged and benign changes are noted
Lymphnodes: No significant retroperitoneal lymphadenopathy seen
Other: No obvious bony lesion is seen. Bladder is collapsed.
Impression:
The imaging findings in the peripheral zone are intermediate ( PIRADS 3). Prostatitis can give similar appearance. To corelate with clinical examination
No size significant pelvic retroperitoneal lymphadenopathy seen.

Most likely an infection. Exercise like bike riding and having sex can increase PSA for a short time, but not usually that much. Sounds like your doc is watching it. That your history shows some decreases is usually not indicative of PCa.