I'm having the same problem! Have they taken this function away? I normally use this very regularly and this is the first time I haven't been able to create a new station. This is on both my mobile and laptop and has been for 24 hours now.
I've found out how to create a radio station again! They've changed it so now you have to search for an artist, then when you're on the artist page there's an option to play their radio station. I have no idea why they've made it more difficult to do this!
the option to play from an artist/album is still there, yup, but vanished from playlists.
I've kind of built up my whole Spotify usage based on the ability to listen to playlist Radio stations, so that I can find new tracks that fit in with that mix of music. If this feature is gone it kind of massively devalues Spotify for me :-/
It's super frustrating - I moved from Google Play Music as I hoped the social and recommendation aspects were better, but so far it's been a real mixed bag. I still don't fully understand/engage with the difference between 'my songs', my thumbs upped tracks, and the ones I <3 from the auto generated mixes. It's really hard to know how best to use the service, and it's made harder when the features randomly change every other week with no warning.