I have pain in my both breasts no lumps though.what could be the reason?

Caffeine/'hormones': Excess caffeine intake is a common cause or just could be premenstrual (or monthly) hormone changes. Fibrocystic breasts may be painful, too and cysts may or may not be felt. The reassuring sign is that it is bilateral. 'infllammatory' breast cancer can present with red skin and pain--so 1-sided symptoms needs immediate attention.