Why can I do the math but freeze on a real-world problem?

Running a clean calculation and making sense of a whole real structure are two different skills, and school teaches the first far better than the second. A textbook problem is already tidied up for you. Reality arrives messy, with too many parts and no obvious place to start. Freezing there is normal. The overwhelm comes from trying to see the whole thing at once. But every real structure is just many small, familiar pieces working together. The skill you are missing is not more math. It is learning to break the big thing down until each piece is one of the calculations you already know how to do. Take your next real problem and do not try to solve it. Just map it. Draw the parts, label the forces, mark what you know and what you do not. Turn the mess into a list of smaller questions. Solve them one at a time. The confidence you have with a single calculation will spread to the whole once you stop facing it all at once.