A high PSA level does not necessarily mean cancer. It can indicate an infection, BPH (benign hyperplasia), or an injury.
A normal PSA level does not guarantee the absence of cancer. Between 10 and 15% of prostate cancers are associated with a falsely low PSA level.
What really matters: The trend. A PSA that increases steadily year after year (going from 3.0 to 3.5 to 4.0) is more concerning than a PSA that remains stable.