Get your basking temperatures up to at least 100F though around 110-120F being ideal. Use large wide sloping objects for a basking spot (be it logs, wood, wide rocks securely stacked, or a cardboard box if that is all you have available) this way the very top of the basking area is in the high range and the sloping sides, range to lower temperatures as you go lower.
Next, get rid of the calci sand. That's about one step up from the worse possible substrate to use. Better to just get non stick shelf liner and cut it to fit your cage, or unprinted plain white or brown paper towel. Or plain unprinted newsprint (that greyish paper kids use to doodle on).
food wise, offer him lots of greens. Stop feeding pinkies. I never feel these are good as a regular food source. The occasional pinky maybe once or twice a month is fine but they should not be a regular item. For now get some silkworms, butterworms or hornworms. These are very nutritious but lack a hard exoskeleton so makes them easy to digest. Feed only a couple of these works (2-4 silks, 1-2 hornworms, or 3-5 butterworms) and his greens. Then leave him alone for a day. If he still regurgitates, even with just greens (if you can't get the worms right away), take him to a vet.
Constant regurgitation can quickly dehydrate your dragon. If he is impacted that could explain why he is regurgitating but the fact he's having regular bowel movements, he isn't completely blocked up. Thus temperatures would be a very likely cause of the regurgitation. Once your temperatures are up as recommended above, he should stop being sick. If he keeps doing it, definitely get him to a vet. Bring a fresh stool sample if possible, he could have a load of parasites too.
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PHLdyPayne