Generally, noYes there are rules prohibiting multiple questions
If you are talking about this question, and that by follow-ups you mean asking multiple questions that follow one another, the answer is no, you cannot ask follow-ups within the same post as the main question. Let's start with the reference rules :
General guidelines for all questions
- [your question] Must be specific and answerable: What problem are you trying to solve?
From the help-center : what topics can I ask about here?
Your question should be specific. Also note that "problem" is singular, with no "s".
What types of questions should I avoid asking?
You should only ask practical, answerable questions based on actual problems that you face. Chatty, open-ended questions diminish the usefulness of our site and push other questions off the front page.
Your questions should be reasonably scoped. If you can imagine an entire book that answers your question, you’re asking too much. From the help-center (again!) : what types of questions should I avoid asking?
Asking multiple questions will tend to make it chatty. Moreover it makes answers much longer than necessary. As told in the tour, the motto of Stack-Exchange is "Ask questions, get answers, no distractions". The goal is to be as straightforward as possible in both questions and answers, and the site is designed for that. Multiple questions in a row tend to attract more questions both from you and answerers, creating long, unreadable threads of comments at best, mangled up mix of answers we don't know what was the question at worst. That's one big reason why it's forbidden.
Finally, know that the community is not overly pedantic. As such some edge-cases are allowed if each question are extremely closely related. For instance : "What is the maximum height of my ogre species? Can it reach the height of an elephant?" Answering the first question effectively answers the second, making this 2nd question more like a writing style to add additional details about what you want (➡️ I wish to make my ogres as big as elephants). This is not really a standalone question anymore. For the other cases... Well, consider you cannot ask them in the same post.
The solution
The solution to this issue is actually quite simple : Don't jump over horses, sharks and sheeps three at a time. Asking two questions at once is not really useful anyway if your 1st question get good answers which are yet inadequate for the 2nd query. Ask your main question, wait for answers, see if you need to know more, then write a second post with your follow-up question. This has been done with success a numerous amount of time.
If you wish to, you can succintly relate one question to another with a link. Just remember that each and every question should hold its own alone, so if you need important details in one question to ask another, you'll have to restate it. This is in part to prevent broken links from making your question unreadable at much later dates... And because it can be annoying to have multiple tabs open to follow you, too 😵.