Where does the prostate cancer spread on our body?

It depends. Not all prostate cancer behaves the same way. However, it can spread to lymph nodes, bones, liver, lungs and brain.
Several areas. Prostate cancer tends to spread over time if left untreated and if it is an aggressive form of the cancer. It tends to spread to local lymph nodes, bones, and surround organs such as the bladder and rectum.
Bones, LN, lungs... Clinically, spreading to bones - spines, pelvic bone, hips, ribs is most common & more than to lungs and regional lymph nodes since bony metastasis is more prone to induce symptoms leading to early detection. Besides, all testing for metastasis is highly insensitive at its early phase of spreading and the cancers spreading to new sites may take weeks, months, & even decades to grow & be detectable.

Related Questions

What are the symptoms if prostate cancer has spread in your body? Do you feel pain in other parts of the body or organs? I feel pain in my legs&knees?

Pain. If prostate cancer spreads, it usually goes to the bone so naturally you would have worsening bone pain. That being said, someone your age is not likely to have prostate cancer (although it can happen). I suggest you visit your local doc and let him evaluate you properly. Best to you.