I have sex with my girlfriend and after 3 days I...

Penis pain treatment :
Treatment depends on the cause, and to detect the cause, a medical examination should be performed and a specialist should be consulted. For treatment, we recommend rest, and not having sexual intercourse during the treatment period. For pain, a pain reliever such as Ibuprofen 600mg can be used twice daily, and in the case of inflammation of the penis, an antibiotic such as Cefaclor 500mg is used twice daily for 5 days, and if the cause is sexually transmitted diseases such as gonorrhea, a Ceftriaxone 500 mg injection is used once, in addition to the use of Azithromycin 500 mg once a day for 3 days
Diagnosis : 
By taking a medical history, doing a clinical examination, doing a blood test (CBC) to detect infections, making a sonogram on the urinary tract and penis, examining urine and semen, and taking a sample of secretions, if any , to do culture 
Causes : 

• Urinary tract infection
• Penile bruising
• Sexually transmitted diseases
• Prostate enlargement