<human>: My dad has suffered with chronic shoulder pain over the last thirty years after he injured it working in the shipyard, and went back to work without the appropriate time to heal. It's essentially a gigantic knot in his shoulder that never releases. (Hey, if you actually have any idea about that kind of stuff, shoot me a message.) 

His main painkiller is oxycontin/oxycodone, but it seems that he has built up a tolerance. As I am typing this, I'm sitting aside his bed at the emergency room. He took 160mg of his painkillers in one sitting, which is way above the prescribed amount he usually takes. (He has 10mg oxycontin, 15mg oxycontin, and 30mg oxycodone in his painkiller arsenal.) He had a doctor's appointment in the afternoon, and his doctor called an ambulance to get him to the hospital. I arrived home to find him not there, and a couple calls later I discovered where he was. 

There is a lot more background, so I'll keep it short. He was on amitryptiline and Geodon which helped with his pain. The amitriptyline interacted badly with another medication (Cymbalta), which led to two hospitalizations. Since then, he's been in constant pain. 

I'm worried that he's built up a tolerance to Oxycontin, and it could lead to an overdose he can't come back from. 

Are there any redditors who suffer from chronic pain that have found a painkiller more potent than oxycontin to manage their pain? I'm actually taking pharmacy tech classes right now and might be able to gain this information from my instructor, but until then I'd like to get all the advice possible. Even if you don't suffer from chronic pain, please feel free to chime in with advice as well. 

Thanks guys.

Condense the text into a few key points
<bot>: My dad overdid it on Oxycontin, in need of a more potent or effective painkiller. Chronic muscle injury, going on 30+ years.