Welcome to Health care Magic.
Before i answer your queiry, i would like to ask you a few questions rergarding your problem.
What is the duration of your problem? Is there any discharge or itching from your left ear?
Most common cause for your decreased hearing would be ear wax
that has not been able to come out naturally. This problem would be worsened if water entered your ears.
Regarding your second complaint, that is pain in the ear, it could be because the wax could have gone deeper in the canal and caused an impaction
on the ear drum.
This could be one possibility, or there could also be a superadded infection to the same ear, a condition called otitis externa
It would be better if you showed this to an ENT specialist
to confirm the diagnosis. Wax could me manually removed if soft, or the specialist would advice a course of wax dissolving drops for a week to soften the same.
If there is a superadded infection he would also prescribe an antibiotic ear drop
I hope i have cleared your query.
Your welcome to ask me any doubts regarding the same.
Dr Hemanth V