Welcome at HCM.
If you are having severe joint pains
, swelling in fingers & stiffness
then most probably it may be RA.You should have TDLC,ESR
& ANTI CCP ANTIBODY test.These are good test & detects the presence of RA.If it comes positive then you may need good anti inflammatory like aleeve with tramdol. There are some disease modifying medicines (DMARD) which do not cause weight gain.These medicines can be helpful to you.
With best wishes.