Is it rheumatoid

Hi. New to group. I suddenly woke up one morning a few weeks ago with my fingers bent. This has continued. My ring finger left hand is almost unusable until I massage and stretch my hands. My GP has run blood tests which showed one marker “slightly high” but this was in line with my blood platelets being a bit higher ( I had COVID a week before test). My X-rays show OA in all small hand joints and no inflammation in fluid in between. My GP says he’s a certain as can be that it’s not RA. Should I push more and ask for an ultrasound or referral to consultant?