Hi
Welcome to the forum!
The symptoms (pain on the left side of my mouth, up to my ear. It is made worse by excessive talking or eating) appear to be due to TMJ or temporomandibular joint disorder. This involves inflammation of the lower jaw joint. It can be due to arthritis or infection. There is a chance that tongue piercing caused the infection or pull at a nerve. It could also be due to a blocked eustachean tube (tube connecting mouth with ear). With sore throat this is a possibility. Try valsalva maneuver (Done by taking a deep breath and blowing while pinching your nostrils and closing your mouth). This will help clear the secretions in this tube that connects the back of your throat with your ear. Try taking steam twice in a day.
However on net and without examining it is difficult to give a confirmed opinion. Please consult your doctor or an ENT specialist regarding this. Hope this helps. Take care!