What is the ruling on masturbation due to increased sexual desire accompanied by menstrual pain, and how can one get rid of it?

Masturbation is reprehensible and has negative consequences, but repentance from it is easy for whoever is truthful with Allah. Your feeling of remorse and your desire to be rid of it are good signs. Seek help from Allah, be keen to spend your time in beneficial matters, avoid solitude, do not dwell on thoughts, and make abundant supplications.