Introducing solids

My baby seems to be in pain after eating solids. We first introduced at 6 months. Tried very little: first sweet potatoes purée, then sweet peas, then butternut squash (each for three days). Within minutes after eating, she turns red, arches her back and grunts. Then all day she would keep doing it and started sleeping terribly. We stopped thinking she was not ready. Just reintroduced at 7 months and it’s the same reaction. She’s been diagnosed with reflux and was just starting to get better and now she’s back to hurting after I tried feeding her a bit of carrot purée two days ago. Anyone had the same experience? What’s happening? Thank you!