Left ear was ringing once/twice previously.. since then my left ear seems like it hears less. but an app hearing test said that i have normal hearing.

Get tested: Ringing in the ears, tinnitus, is not uncommon. You should see a ENT doctor to get tested and rule out treatable causes. You may consult this site for information on this topic: http://www.mayoclinic.org/diseases-conditions/tinnitus/home/ovc-20180349 For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex.