Suggest Treatment For Rib Cage Pain With Heavy Menstruation

Please Help,
Pregnancy symptoms of exhaustion, dizziness, light headiness, pain under right rib cage, etc; all symptoms went away accept for the pain under right rib cage and now with very heavy menstrual. Pregnancy test (blood and urine came out negative). I am also taking Synthriod for having a total thyroidectomy (summer of 2009) but nothing has been wrong until now where my thyroid levels were low and increase in medication (Synthriod 0.75 to 1mg).

Thank you in advance for any input into this matter.