The old adage of restricting salt and even restricting water intake backfires. It simply sets in to motion the body's reactions to retain more salt and fluid. Drinking clear liquids flushes out the system. Many herbs and viatmins are suggested. Vitamins B and E have been looked at scientifically and have NOT been shown to work.
Primrose oil has fairly strong evidence of effectiveness.
Vitex agnus castus has some limited evidence. One of the simpliest solutions is a more supportive bra. Underwire, that is properly fitting, for daytime. High impact, compression bras for sports. A woman should go to the doctor if the breast pain is interferring with her normal activities.