I have bad lower back pain for a week, it also radiates at times into my lower abdomen (feels almost like contractions) same thing a month ago?

R/O SCIATICA . Your age and description of symptoms is suggestive of sciatica. You need a full exam and focused Neuro exam with reflexes Checked. Also X-ray of lumbar spine and if no improvement an MRI to rule out arthritis a bulging disc or congenital back issue. Till then no heavy lifting .
Lumbar strain. more than likely this is just a strain but since it is now the second time I would recommend you go to spine specialist to be evaluated .
Pinched nerve? this could be a pinched nerve. It is best to have your physician evaluate because the level is higher than we usually see with pinched nerve. There may be another abdominal issue also. This is where your phydician's evaluation will be valuable.