There is no break between Revelation 10 and 11. Whoever made these chapter breaks missed the very obvious flow from one to the next. The chapter break would have been better inserted at Revelation 11:15, when the seventh trumpet sounds. It would have made for a long chapter 10, but it would have kept similar material together. Perhaps Satan had a hand in this, because the original Bible did not have chapter breaks. Maybe the Devil was able to influence some scribe somewhere to do this and confuse the interpretation of these prophecies. I do not know. However, we need to see these chapters as a whole.
This section is what we could call "an inset chapter" or "an inset passage." It is a digression from the main flow of the chronology - the main flow of events. It takes time out to explain an important subject so we can get caught up and understand what is happening more fully. There are several of these in Revelation: Chapter 12 discusses Israel and the persecutions that come upon it - and later the church, the Israel of God (Galatians 6:16) - by Satan. Another well-known one is chapter 17, about the harlot that rides the Beast, and chapter 18 is the description of Babylon. These insets give us important prophetic information that we need to know.
It is important that we understand this point. The seven thunders and the eating of the little book in chapter 10, as well as the measuring of the Temple and the Two Witnesses in chapter 11, are all part of one major subject. What is this major subject? If we know what the seven thunders are, what eating the little book is, what measuring the Temple is, and what the preaching of the Two Witnesses is, then it becomes quite clear. What do they all have in common? The message and the preaching of that message.
Revelation chapters 10 and 11, then, are an inset passage on the preaching and work of the church - especially its leadership, those messengers God has called to proclaim His Word.