My mother is having weird feeling in front area of leg below knee.i think its called shin.and weakness in legs.its not pain actually .its something else which she can't describe.she keep sitting for sometime then do some work. Only that area feels something different and there is weakness.she says it feels that she is too tired but that is not the case.what it could be.is it related to arthritis?or nutrition deficiency.2 mnths bck she had mild covid.she is damn scared of mri.