Talk to Gynecologist on Conceiving

I am 27 weight 46. 1.5 year married. I found very difficult to do the deed as I was going through vaginismus or something else that was not making up my mind to do the intercourse. I used to push my husband back all the time. After 10 months I finally did it but I am still unsure that if it is done properly or not. We don't do any missionary position. The only position that is comfortable to us is when I am on top of him. I don't know if it would help me to conceive or not.

Any other positions are unsuccessful for us. My husband weight is much and he is unable to do it in missionary direction or related to that.

Please guide me what can I do to concieve.