HSG for recurrent pregnancy loss - experiences?

Hi ladies, so I know my next plan is to have an HSG for recurrent pregnancy loss. Waiting for my Hcg levels to drop from my last early miscarriage (it's taking forever - since August and it's in the 20s). Hopefully within the next month it will drop and my doc is ready to do an HSG, as he is suspicious of a uterine septum. So..... anyone who has had an HSG can you share 1) why you had it done 2) the pain/experience 3) results 4) and influence on future pregnancy? Thanks so much!!