A week before my period comes I get painful, sore & tender breasts. I know it's a common PMS symptom. Can I treat or prevent it?

Management,,, Likely the best way to deal with this is to manage it. A wide range of things can be done. To start with, diet and exercise, like reducing salt and caffeine might help. Also, especially here, anti inflammatory meds like naproxen or ibuprofen could help this pain. Oral contraceptives/birth control pills could also help here to balance out the hormone swings. You can see your Dr. To be sure.
Things to try. Omega 3 fatty acid and magnesium supplementation can be beneficial. Avoid excessive sugar and low quality carbohydrate intake. Don’t add extra salt to your food and avoid processed foods containing extra salt. Reduce caffeine and alcohol use. Stay physically active.