Why Do You Get Swollen Glands Before Your Period I Get A Pain, And Swelling, In My Gland Under My Arm Pit 2 Weeks Before My Period?

I get a pain, and swelling, in my gland under my arm pit 2 weeks before my period? - why do you get swollen glands before your period

IV had this problem for years, can I change my gland drainage? My other question is that I know because of my glands always, my rules, just as I try to understand when to stop the swelling in prega.