Hello and thanks for posting,

It does not sound like your GP is particularly worried, and he has checked you for obvious lumps in the testicle. It is good to be body aware, but testicular cancer isn't very common, and other causes are more likely. 

Inflammation and irritation in the testicular area is common, and can take some time to pass. It can be due to viral or bacterial infection, or after exercise. Burning sensations are not usually a common sign of testicular cancer. Sometimes GP's prescribe antibiotics too, if they think there might be an infection in the area. Sometimes cysts or knobbly veins in a testicle can cause discomfort. 

Refrain from strenuous activity, especially cycling. Bathe or shower in tepid not hot water, and wear loose underwear (briefs) for now. Try and change your position, and don't sit for long periods at a time.

There is more information here, 

https://www.nhsinform.scot/illnesses-and-conditions/sexual-and-reproductive/testicular-lumps-and-swellings/

https://www.nhs.uk/conditions/epididymitis/

If it doesn't resolve, then go back and see your GP. Try and not over think this, and keep yourself busy and occupied. 

I hope that this helps,

Best wishes,

Vanda