M.R.
Just asking...is she really constipated?
If you are breastfeeding or (since I see the word 'bottle' in your request) feeding expressed breastmilk, it could be normal that your child would go several days without a BM. Formula fed babies have their BMs a little more frequently.
When she does go, what is the stool like? If is pasty like peanut butter or is she producing small, hard, dry pellets? If it is pasty, then she's probably not constipated - just do things as you have normally been doing. If she's passing dry pellets - that's a sign of constipation.
Quite honestly, if her BMs are normal-looking then you are potentially only stressing her digestive system if you keep adding different things like karo and suppositories (these could be the things causing the gas pain). A much better alternative might be to give her a bottle with prune juice that has been heavily diluted with water.