SI Joint Dysfunction. Or any other?

The problem/pain started in my left lower back & hip area after a workout session in gym. Apparently I lifted little more weight in "Dead Lift" exercise that day at the gym. Slight pain started on the spot which is normal during workouts, hence I took it as muscle pain and thought it will be gone in 3-4 days like any other muscle repair pain but it Increased. So then I went to a Physiotherapist, He diagnosed it as "Sacroiliac Joint Dysfunction" so then I took sessions of IFT with Hot Pack. He also taught me some exercises for the problem. The pain decreased from 100% to 10% within a week but that 10% of pain/discomfort/irritation took 6 weeks to go away with proper exercise and rest. Now that 10% of pain/discomfort/irritation is back again and any sort of physical exercise causes it. I want to know that what kind/type of doctor to look for? "Orthopedist", "Physiotherapist", "sports doctor" or any other? coz IFT sessions just suppresses the pain but I want proper solution.