I've had excruciating lower back pain (had l1 compression fx two yrs ago) for past 5 days and waves of nausea for past 3 days. could they be related?

Possible but----: I suppose it's possible to have the nausea you're describing on the basis of medications you're taking for the pain or perhaps just a SEVERE worsening of the pain itself for some reason. However, you also need to look at other causes since you've had the back pain for 2 years I wouldn't expect nausea as you describe to just "pop up"...you should see a doctor or get a consultation here on HealthTap