hello and welcome,
you had an injury
while lifting heavy weight in the gym,. your MRI
is normal, you have taken medicine for inflammation and had applied local pain relievers ,. this all has decreased your pain to some extent but not completely.
sir, you can very well return to the gym as soon as possible , but before that take some physiotherapy
for your self, this will definitely make the injured and inflammed muscle come back to normal with no pain in the day to day activities.
once there is no pain in the muscular area, you can very well start gyming but don't exert the muscles on the first day itself , start with easy exercises and low weight till the muscle get back its strength and then you can consider yourself normal for any activity.
hoping you get well soon.