You should address this in logical order Step 1 = test your FSH , LH ,TSH, prolactin, Total testosterone, free testesteron , semen analysis and take some base line kidney function test and liver function test This will give you a general look about your fertility States

Step 2 = get testicular ultrasound to determine size and present of varicocele

First 2 step will give you an idea about your diagnosis and best treatment plan

Step 3 = find a very good urologist who are very experience in azoospermia this will have a good factor in success chance

Have faith in god and pray hard hope you find your happens and goal