I Have Been Taking Estradiol 1 Mg For Several Years.

I have been taking Estradiol 1 mg for several years. My 3 month prescription came in the mail and the pill is from a different mfg. The pill I have been taking for several years was from Barr Lab oval purple pill 886/1 b and now the pill that came in the mail (Humana) is from mfg. Watson Labs pill #487. I am taking the Watson Labs pill for about 2 months now and I have experienced breast pain.(feels like the pain is in the tissue of the breast.) This morning I woke up and it was really really bad pain in the breast. Can the difference in the inactive ingredients in the estradiols cause the pain I am experiencing in the breast?????????? I saw there is a difference in the inactive ingredients. I called my obgyn and he said to take the pill every other day and see if that helps if not call back. What do you think????????