Hello dear
Understand your concern.
It is not 
testicular torsion it is medical emergency, in which 
severe pain along with redness is there.
I think it may be  trauma or epididmytis or orchitis as it is since last three week.
Other causes of 
testicular pain are below:
Chronic Prostatitis, Kidney stone, Hydrocele, Cancer of testis, Vericose vein of testis, Hernia, Cyst of epididymis,  STDs (syphilis and gonorrhoea)
You should consult the surgeon and do following test for diagnossi
1. Blood: CBC, ESR, PSA, Glucose, Urine: Routine and microscopic examination
2. STD screening
3. USG of scrotum and abdomen
4. Biopsy should be take from testis
5. 
Rectal examination for prostate, testing of prostate fluid
All this help in diagnosis
Advice for you:
Tablet ibupufen 500 mg two times a day
Tablet Cefuroxime 400 mg two times a day
Avoid sex
Avoid heavy weight lifting
Wear supporting device and elevate the scrotum
Wear loose inner wear
Warm bath
Hope this may help you
Best regards
dr. Sagar