My 95 mum is suffering terribly with knee arthritis and now neck pain which goes up the back of her head and today she says it hurts when she chews .She is on morphine patches and oramorph as a top up .Which doesn't seem to touch the pain.It hurts every time she moves her head and she is in agony when she walks with her arthritic knee that they can't operate on .can arthritis cause that much pain ?