5th Metatarsal Broken Again?

I broke my 5th metatarsal in my left foot, I was in an aircast boot for 5 and half months as the bone would not heal.  I am still getting pain in my left foot.  Two weeks after having my boot off I  broke my 5th metatarsal in my right foot, it is exactly the same fracture (spiral) as the other foot.  I am now in plaster and non weight bearing for 6 weeks.  When I go back if the bone has not healed would surgery be needed?.  I have previously broken my heal bone in my left foot, in 4 places (4 yrs ago) which also took 5 months to heal, I have also broken a bone in my right ankle roughly about 8 years ago, could there be a bone problem?, Do I need to get my bone denisity checked?.  Other than that I am a healthy 27 year old, I have a good balanced diet and have a good calcium intake.  Your help and advice would be greatly apreciated as I am fed up of having broken feet.Please help me, thank you