Thanks for the question,
, also called olecranon bursitis
, causes fluid to collect in a sac that lies behind the elbow, called the olecranon bursa. A bursa is a slippery, sac-like tissue that normally allows smooth movement around bony prominences, When a bursa becomes inflamed, the sac fills with fluid. If this is infected then it causes pain.
Better to consult with orthopedic surgeon also and meanwhile apply burden gel and avoid trauma on elbow.
Bye for now
Dr Sher Bhutto