You are still healing, and I'm quite sure that it is directly related to what and how you're eating. Now that you have a wrap created out of your stomach, things have a harder time getting through. Because of this, your wrap can get irritated, and you can even have a bit of food/drink/even medication sitting on the wrap site at the bottom of your esophagus, which can also be irritating.
Be sure to continue to take very small bites and chew, chew, chew your food. Generally when people get to the stage where they're adding a bigger variety of solid foods it's pretty common to get some feelings of pain or irritation. You're still healing, and need to listen to your wrap. You may need to baby it for a few days.
Also be sure to sip on water or tea after eating so you get more swallowing action and ensure that all your food actually makes it into your stomach and isn't sitting at the base of your esophagus fermenting and irritating things.
This situation will improve a lot over time. Still, even after you're fully healed, you may find that you get some irritation depending on what you're eating. Raw veggies can cause my wrap to get irritated if I eat a lot of them. Be sure to always drink plenty of water and sips afterward, whenever you take medication.
It will get better!