I am a GP and have a lot of experience of working with people with arthritis (23 years worth!) and I think it is much more likely that your arthritis is osteoarthritis, the wear-and-tear type.
Rheumatoid arthritis most commonly starts in the 20s to 40s and is 3 times more common in women.It would be unusual to be starting with it now.
I am concerned that in view of your gastric reflux, for which you are on treatment, many of the drugs mentioned above could make this condition worse, in particular ibuprofen and any related drugs (commonly called NSAIDs).Avoid buying neurofen over the counter, but paracetamol is safe.
There is evidence that a good diet rich particularly in Vitamin C, beta-carotene and vitamin D can help osteoarthritis.
This is a great article that goes into detail about which foods can help and also has information on wacky (usually expensive) diets that make no difference at all.
There is also a supplement called glucosamine which has been shown in some studies to help with the pain and stiffness of arthritis.It is a naturally ocurring substance that you can buy in Boots or health food shops and is well worth considering.(It is derived from shell fish so if you have a shellfish allergy you need to be careful.) You can read more about it here.
As you can see there are quite a few self help measures you can do for this.
Keeping active is also known to help with arthritis.
I hope this information helps.