Tibia & Fibula Fracture & ORIF Surgery.

I met with a Car accident on 29th Mar 2019 & broke my Tibia & Fibula. I went through ORIF surgery on the same day & Stainless steel Rod has been inserted by the doctor. I was completely on my bed rest for 60 days since my surgery as per my doctors advice. After 60 days I visited my doctor for the final review  and doctor advised me to walk without support itself after complete examination of my broken leg and x rays. But I could not work on the same day without support but I started with Walker support. Today is 90th day since surgery e and I am working with a a Cane stick, but my question is when I start walking everytime, in the beginning of 4 to 5 minutes I would be having severe pain in the broken area, after 5 minutes I can walk with little bearable pain, how can  I avoid/reduce this pain? Please advise... Thank you for your kind advise & time in advance.