I agree with kay regarding the importance of seeking help from a pancreas specialist. Without knowing what treatment you received whilst in hospital for all that time it's impossible to know whether something else entirely might be causing your symptoms which are not usual for pancreatitis, acute or chronic.
Whilst the pain can be severe and impact on one's ease of mobility for the duration of a pancreatitis attack, it's not common to be unable to remain upright for longer than 15 minutes ongoing. The shoulder pain may be referred from your pancreas, or it could be as a result of something else entirely.
What you're experiencing, especially the severity over such a long period is not normal for anyone, with or without pancreatitis. You should see a pancreas specialist asap. Your GP can do some tests as well as organise a specialist appointment for you, or you can return to the hospital to report what's happening to you and arrange a specialist appointment.
You say nothing about your diet or medications, in fact anything about preventative measures so I'll list them, forgive me if you're fully aware.
It's very important to adopt a low fat diet, there's no getting around that, you have to, it's not a choice.
In a general sense eat 4-6 small meals throughout the day rather than 3 large meals a day to help your pancreas.
Ensure you take your digestive enzymes immediately before any food at all, even snacks. They last for 30 minutes, so if having a long meal take more enzymes after 30 minutes.
You have to give up alcohol entirely. And same for cigarettes, your pancreas hates smoking.
It's important, especially when attack coming on or during attacks that you reduce food, even stop eating entirely for a couple of days to rest your pancreas. Have clear broth if you can cope and keep up your fluids, frequent sips. If having a severe attack you need to be in hospital where you will be on an IV for as long as necessary to ensure nutrition and fluids are kept up as well as pain management. I wish you well.