This trial is testing a new medicine called **safinamide** to see if it helps with pain for people with Parkinson's Disease (PD). PD is a brain disorder that affects movement and can cause pain. Safinamide will be compared to a **placebo**, which is a fake treatment with no medicine in it. This study wants to see if safinamide can reduce pain better than the placebo. - **Study Length**: The treatment lasts for 12 weeks, and the whole study will take 24 months to complete. - **Visits**: Participants will take safinamide or placebo daily, with doses increasing after the first week. - **Risks and Benefits**: Possible benefits include pain relief, but there may be risks like drug side effects. Participants must be at least 18, have had PD for 3 years, and experience motor issues and pain despite taking levodopa, a common PD medication. Women in the study must take a pregnancy test and use birth control. Some people, such as those with certain other illnesses or using certain drugs, cannot join the study.