My father who is 64 years old is suffering from lower back pain which was intermittent initially and appeared like some form of ligament tear of muscle strain pain thst comes suddenly on getting up or bending down to pick something. However over a past year or so it has somewhat turn to be of a chronic situation where he most of the time suffers from the pain.. the pain exactly is not excruciating but however disrupts the normal routine.. he can still drive or do work but feels uncomfortable. His weight is 70 kg and is apparently healthy.. has no history of hypertension,
diabetes mellitus or any sort of allergy. He stays physically active throughout the day.. What might be the cause?