no start sometimes

[varover]

96 rover.(orginal owner) would not start, lot of clicking. jumped she ran, put on battery charger, still no start, jumped started. next 3 days started great. went to store came out dead, jumped. shop says battery has low cell and get a better one. there was no sign that battery was going bad. like it went from great to bad over night. When this all stared, i heard, or felt a thump like i ran over a stick, no stick seen. even when jumped it starts a little slow.
Anyone know a good shop in Virginia Beach va??
thanks for any help