Talk to General Physician on Left Shoulder Pain

I have a severe issue of left shoulder pain. I have been experiencing it for more than a year. I don't exactly remember when it started. But my left shoulder aches alot. Whenever i do some tiring work my left shoulder starts to ache alot. Earlier i got it checked from a doctor. He gave med but it was a temporary relief. I am a teller by profession and counting cash from 9:00 am till 7:00 pm becomes very much hectic. Day end tk mera kndha itna drd kr rha hota k main ghr ja kr khana khaty b thakk jati hun dil krta bass lait jaun. Srf lmbi neend ly k uthun to drd khtm hota agr next day phr utna e kaam krun to tkleef utni e hoti jtnu roz hti hay aur mjy bhhht shdeeed drd hota hay left shoulder main. Pain ahista ahista strt hti aur phr itni brh jati k brdasht sy bahar hujati. Plz guide me. Any home remedy that i can do everyday and that can ease me. Please help. Chutti waly din theek rhta. I'm unmarried and this makes me more worried that how would i cope up with this issue in future with k