Ask outside opinion. If you record what you’ve got you could send it to me and I could make some suggestions, or get some of your musical (or non musical) friends to tell you what they think, or how the song so far makes them feel. Someone going “this makes me remember when my grandma died/I met the love of my life/had my first daughter can be huge inspiration and all you need to push it forward a little.
Alternatively, a good way to get back on track when you’ve stalled at the lights is to work on a different part of the song. i.e, if you have the chords for the verse and chorus don’t work on the chords for the bridge, work on the lyrics or the drums for the bridge, then you may well find that the chords will follow soon after.
Don’t push it. Take a few days off from writing and only listen to music that you hate for a whole day. If you intensely dislike commercial hip hop, blast out 50 cent in your car on the way to work.
This is a little like cleaning out the cobwebs, and can do wonders for getting rid of the stagnating mush in your brain that comes from only listening to things within your comfort zone.
xx