I am day 6 of having covid and isolating. after day 2 i developed severe muscular type pain at my lower right side of back. it is painful when i move or turn. should i be concerned about this pain? what could cause it?

I do empathize with you, but the virus like most viruses could affect virtually all the organs including the muscles, there is also possibility of muscle strain regardless of the Covid infection. There are medications available to limit the extent of severity that you may try to access if there are worsening symptoms or underlying disease. Muscle massage or warm compress may help the soreness.

I agree that heat applied locally may relieve your muscle aches. This is a common symptom of COVID 19 and other symptoms would be helpful to describe. Do you have. congestion, fever and a cough? Please monitor temperature and breathing. Watch for shortness of breath, prolonged cough and keep well hydrated.