The olecranon bursa can become inflamed or irritated either as a result of local events or as part of a systemic inflammatory disease. A few are infected. Most are local and sterile but consider and try not to miss the others.
Aspiration with aseptic technique relieves discomfort and allows inspection and culture of the fluid to exclude or diagnose infection. If the fluid does not look infected, injection of 100mg hydrocortisone or a suitable dose of a suitable steroid preparation is common and seems to speed resolution. Complications are more likely with the steroid and culture is mandatory.
It is traditional to record the volume aspirated. It will be about 20ml.
Pressure after aspiration - with tubigrip or something more durable - seems likely to discourage refilling. Whatever caused it should be avoided if possible, at least for a while.
Hardly anyone needs excision of the bursa.