Hi @Lyn_li yes you're right, this could be arthritis and if unprovoked, the commonest cause is age-related changes in the bone and/or cartilage at the joint surface. However, there are many other possible causes that may require further examination and potentially a scan, especially if there was any injury or trigger preceding the onset of symptoms. What therapy would be effective would depend greatly on the underlying cause, and if the pain is bothering you then you may want to consider a review with your physician to determine this. Apart from the level of pain, other features that should prompt you to seek a review are the presence of any preceding injury or accompanying symptoms such as rash, hair loss, or photosensitivity (if you find your skin is unduly sensitive to sun light). Hope this helps!