painfully shy - extremely shy, or so shy that other people fin | Useful English
painfully shy - extremely shy, or so shy that other people find it disturbing
Examples: Paula was painfully shy when she was in high school. The fact that she was so painfully shy embarrassed her parents and annoyed the other kids.
Video: On one hand, you're painfully shy and on the other hand, you say these things that I don't think I could ever say. Almost Friends (2016)