Protagonist with 2 goals?
Question: I am working on a book for a musical. Question, can the protagonist have two main objectives...for instance, one to achieve his dreams of becoming a rock star the second to find love? Or will two main objectives be confusing/overkill to the audience and make the foundation of the story shaky?
Generally, if the protagonist is also the main character, he will have two problems to wrestle with, but they will be connected.
On the one hand, he will be pursuing the overall story goal. In your case, I suspect that is the goal to become a rock star. Usually, this goal is something the majority of characters are concerned with in one way or another. This is sometimes referred to as external conflict or external goal.
At the same time, he will have an inner conflict to resolve, the crucial aspect of which is whether to stick with his established way of being/doing or change and follow the example set by the impact character. (In a romance, the impact character is usually the love interest, though not always.)
How the main character resolves his inner conflict will determine whether or not he achieves the story goal.
For instance, let's suppose the girlfriend has a different approach than the main character. Because of her example, he decides to change at the crisis and adopt her approach. Because of that decision he is able to achieve the story goal. Result: happy ending.
On the other hand, it could turn out that the impact character has it wrong and the main character decides to stay steadfast, forcing her to change and adopt his approach. Result: also a happy ending.
Or, it could be that the impact character has it right, but the main character rejects her advice and stays steadfast. Result: tragedy. He may lose the goal and the girl.
Or, maybe the impact character has it wrong, but the main character follows her advice. Result: he gets the girl but loses the prize. (But maybe that's okay?)
What creates tension for the audience is that neither they nor the main character can know what the right choice is until after it is made.
You have to decide...
1. What kind of ending you want (happy, tragic, or in-between).
2. Whose approach is right in the end.
3. How the main character will choose to resolve his inner conflict.
4. Whether he gets the girl.
Like I said, you can also have another character serve as impact character. The above is just a popular arrangement.