Thanks for your query.Based on the facts that you have posted it appears that you have simple cortical cyst
in on left side. This cyst is congenital in origin and does not need ant active intervention.
The size of the prostate
of 31 cc with post void residue of 32 c.c indicates Benign Enlargement of prostate.
This can be managed by medicines
Consult qualifies Urologist
for further treatment. He may advise you alpha blockers like Tomsulosin once a day.