It seems like you tried get a ryhme scheme going and then abandonded it.... which is fine... sounds good as I read it out loud. I would suggest using the second phrasing as a chorus its the most catchy... As for the chords... tune your guitar to drop d... drop c if you can without needing a setup... and start chuggin away on the top 3 or 4 strings... it shouldn't take long to come up with a nice heavy riff to go with that.