When is an MRI recommended?

I'm not a doctor !!! but i request a MRI after two doctors send it me to work, they do X-rays 3, chiropractic , but I just was work with ice pack on my back for 12-14 hrs a day and pills, is was something wrong, I'm got a lawyer they do MRI and they find a hernia bulge disc in the lumbar area, to inside off the column, the doctors and even X-rays cant diagnose to many things.