Hi Sharon
The breast pain you describe could be fibrocystic breast disease. This is a
very common condition clinically present in up to 50% of all premenopausal
women, but presenting in a range of ways from slight breast tenderness
premenstrually, to chronic, noncyclical pain. Other women experience lumpy
breasts, or nipple discharge.
The 'disease' (not really a disease, more an abberation of normal development)
usually has its onset in the third decade of life and peaks in the forth,
decreasing with the menopause.  It is considered a benign condition with
no effect on breastfeeding, but those women with epithelial proliferation
within their breast (whether related to fibrocystic disease or not), have
an increased risk of breast cancer of a factor of 2-4.

I did a literature review of fibrocystic disease last year for a paper I
wrote for the Lactation Resource Centre in Australia. It seems that there
is still much disagreement about the exact cause of the problem, and hence
treatment is still varied and different things work for different people.
It is generally agreed that the noncyclical pain is harder to treat than
cyclical pain. Suggested treatments are methylxanthine (caffeine, theophylline,
 theobromine) reduction eg tea, coffee, cola etc, stopping smoking, reducing
 tyramine rich foods in the diet (mature cheese, wine, mushrooms, bananas
and processed meats), Vitamin E (600 IU per day), Evening Primrose Oil
(1000mg three times a day), reduction in dietary fats, or treatment
with medication such a progesterone, oral contraceptives, danazol, tamoxifen
or bromocriptine (all heavy-duty treatment which would only be used as a
last resort). It seems that most treatments have to be used for several
months before any benefit is seen. Sometimes general good health like diet
regualr exercise or massage might be effective, at least from a mental
point of view. I have quite a few references if they could be of use.
Hope this helps :)

Fiona Coombes
NMAA Breastfeeding Counsellor
Family Physician, IBCLC