Hi and welcome to HCM. Thank you for your query.
Your knee pain
is probably related to your testicle pain
because it has the same inervation and also there can be refered pain too. YOu should evaluate this swelling,it can be hydrocele or hernia. YOu need to ultrasound
and consult urologist
. Till that,avoid long standing and do urine analysis. Wish you good health.