irritation and reddness on penis

i have been experiencing  a irritation on my penis that comes and gose after sex.  i mean when i have sex with my wife afterwards my foreskin and head of my penis gets red and is somewhat painful.

[Dr_Aparna]

Hi,
Painful sexual intercourse is called dyspareunia is less common in men than in women.
Pain during intercourse  can be caused by infections, either balanitis(inflammation of glans (glands)) or a sexually transmitted infection.
Pain at ejaculation can be caused by an infection of the prostate gland or urethra.
Pain at tip of penis after intercourse can be caused by thrush infection (candida)-a fungal infection or due to an allergy to contraceptive cream or condom.
You may be prescribed antibiotics for infection or creams for thrush or allergic reactions. Water-based lubricants may be helpful if lack of lubrication in your partner is the problem.
ref:http://www.irishhealth.com/index.html?level=4&con=110
Hope you find this information useful.