What Causes Cracked Noise And Severe Pain In Metatarsal Break?

In 2011 I had a 3rd metarsal break. I went 14 months diagnosed with a sprain from 2 doctors. Never got better a lot of pain.. In 2012 sent me to a 3rd dr. and he found I had a nonunion 3rd metarsal break.. But in plate a screws and bone graft. Went through the whole healing process and he released me with it healed and never got better. After another year 2013 then 2014 had another dr, he found that plate had broke.. Last June put it in a bigger plate screws and fused stayed that healed. But know I notice the cracked noise and more pain and looks like screws are broke again.. What do you do after that?????? Of course they say a 1 before plate but we might be looking at broken for the second time.......