I'm on soft food phase. I get all my protein in which is about 100g and is about 360 to 400 calories. I'm afraid to eat anything because I don't want to go over 500 or 600 calories

My nut has said repeatedly not to worry about calories, and just to focus on protein and liquids. So I'm trying to follow that advice. However, on mfp it kind of forces you to focus on calories. So it's hard and I don't have a good answer, but I think you have to be way low.

From everything I've read and researched, 600 would be the absolute low end of the number of calories you should be getting by that phase.

I am in soft foods and having issues getting over 500 most days

600 is the minimum, this sounds crazy but you actually WON'T lose any weight if you don't eat enough!! Just focus on getting your protein and fluid requirements in, I know MFP makes you count calories but try to ignore that number and focus on protein and maybe when you're ready carbs. I was told 3 meals a day with a minimum of 20g protein at each sitting and a max 30g of carbs at each sitting and that works for a lot of people however while you are fresh out of surgery it's 100% normal to eat little meals more often because it's unlikely that you will be able to tolerate 20g of protein in one sitting while you are still swollen. Focus on requirements and exercise and please don't fret the calories just yet, your body needs them to heal!