All of these side effects seem to be normal. I have been using it for ~4 months and the hot flashes have not gone away. I get them every time for about 30 minutes. The upset stomach I believe is just hunger. I have the most problem with it at breakfast when my stomach is completely empty. I just ignore it.
The soreness......I have not found an explanation for this one but it seems common. I am not physically able to train 6 days a week now. I did a heavy chest/triceps workout Tuesday and was no able to train again until today. My shoulders and elbows were aching and the DOMS was horrible. I am having to take 1-2 days off periodically between heavy training days. But the growth and strength gains are still coming so I can't complain.