Well, the fact that the pain and swelling are recurring and may be their frequency or/ and severity have increased since the time of their onset so it becomes invariably important to explore the knee joint and the tissue around it because there are various possibilities which could be causing these symptoms such as 1) stress fracture owing to the nature of your profession which requires continuous walking and standing thereby affecting your knees where the body weight is relayed on, 2) ligament tear, 3) Arthritis ( Rheumatoid or Gout ), 4) Neuro-Muscular spasm etc.
So to gain more insight into the possible cause which is leading to this problem, you need to get yourself physically examined by your doctor and get the below tests discussed and done such as
-- X- ray rt. knee
-- RA factor for excluding rheumatoid arthritis
-- Serum uric acid to exclude gout.
While you get these done you may start applying a warm water bottle over the affected area of the knee for at least 20 minutes twice or thrice a day. Do this for 5 days at least
Other than this you may also apply a topical analgesic ointment ( i.e diclofenac sodium ) over the affected area two times a day and continue this for 5-7 days
Lastly ask your doctor to give you some simple painkillers which you shall take for 5 days.
The above mentioned strategy may relieve you of your symptoms but the physical examination and investigations advised shall throw more light on the plausible cause behind this symptom and put to rest all the confusion surrounding this issue.
I hope this makes sense.
Wish you all the best.
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