Rheumatoid Arthritis Treatment

Hi all,
First of all I have Psoriatic Arthritis, which is very similar to Rheumatoid but Psoriatic is more aggressive. I’m 26 and have arthritis all over my body. I’m under hospital treatment and take an ex-cancer drug (Methotrexate) but have been switched to Enbrel now.
I’m having problems with pain management. I take a higher dose Cocodamol at the moment with the highest dose of Diclofenac but it’s not working. I’m in a lot of pain. They are tying to put me up to a different painkiller but I have problems with my liver acting up when they made my painkillers stronger last time.
I don’t know what to do as it’s so hard coping in pain all the time, but then having liver problems when they make them stronger. How do you cope? Have you found a certain painkiller to be wonderful? If so, please could you tell me the name of it and what dose you are on. Thank you.