certain songs can't be played through my phone's spotify. but every song can be played perfectly fine on my mac. and my account's premium
Lets try to get a little bit more information to see what might be going on.
First is there any content that has been downloaded to your device, have you set the Spotify app into offline mode?
Check this Spotify help faq link with regards to offline troubleshooting: https://support.spotify.com/using_spotify/troubleshooting2/offline-troubleshooting/
Also can you post back what mobile device you have, OS, and Spotify app version?