Hi KatyMac
New to mumsnet - hope it's OK to jump in and comment on your thread.
Just wanted to say that normal range for ESR is up to 10, so 55 isn't just slightly out of range!
Also, apologies if i'm telling you something you already know, but you can have inflammatory arthritis without rheumatoid factor - it's called sero-negative arthritis.
The symptoms you describe re: general pain/joint pain/bone pain and cold hands/feet are very similar to how my arthritis started out.
Apologies if you've already been down this route, but with your symptoms / ESR result you should really be referred to a rheumatologist as they have the specialist knowledge to evaluate you properly for arthritis.
For example, you can have almost normal blood test results for ESR/CRP and still have inflam arthritis - I have been crippled to the point where I cannot walk by my arthritis and only had ESR / CRP results in the teens and twenties. I've been told that people with sero-neg arthritis do sometimes have limited changes in their inflammation markers (CRP/ESR) which can make it particularly hard to diagnose.
I was seeing a doctor for months with what I know now to be quite obvious symptoms of arthritis and they couldn't work out what was wrong with me - that doctor was off sick when yet another set of my blood test results came back and I was incredibly lucky to have a different doctor at the practice, who had more knowledge of auto-immune conditions, review my results - he worked out what was wrong with me and got me off to a specialist ASAP. Seeing a rheumatologist was just the begining for me - took a long time to find the right meds, but at least I was on the path to getting better!
I hope you can get the help you need - there are so many meds to try these days that there's a good chance if it was arthritis you could get it under control and get off the painkillers/lead a happier healthier life!