Pain in left shoulder. To my shoulder.

Almost 1.5 years ago,when i am in gym,I am doing chest weight lift,I feel some pressure in my left shoulder because weight is high according my strength.Next day there was pain in my Lt shoulder when I am doing shoulder exercise and it is increasing day by day,then i left the gym.Then after few months when i again join the gym the mild pain starts again.After that i again left the gym.Then now from last one year there is mild pain occur sometime,I consult doctor also and he suggest me to do MRI and MRI report was normal,there is no abnormality.I do all my daily work easily,but i am not able to do exercises like pushups.,when i do,pain starts again,from last one year i am giving complete rest to my shoulder i also not pull any heavy weight from my Lt shoulder,but the things was as it is.What should i do now,is there any serious problem.Please suggest me something what should i do now related to my shoulder.