Hsg testing

Has anyone done a hsg test to see if your tubes were blocked? I have never had one done. I have been ttc for 15 months now and I'm not sure if I should talk to my doctor about it. I am on metformin and did two cycles of clomid with no success. What should I expect with this test and does insurance cover it or is it usually all out of pocket cost? Any advice would be appreciated. Metformin made my period regular since October when I started it however the month if February no period and two negative results. I'm just feeling lost and need advice on what to do next if anything.