Maybe it's the weather, but I have lower back pain.

My lower back often gets sore. There was no particular movement, but suddenly I felt a sharp pain as if something was caught, and my lower back collapsed, making it hard to move. I went to the hospital before, and I was told it wasn't a disc problem... they said my poor posture causes lower back pain. I'm trying to correct my posture... and I also do Pilates exercises as a preventive measure... but sometimes I feel more pain after doing them, so I'm 고민 (worried/conflicted). In the morning, my whole body feels stiff and heavy, and it hurts... maybe because of the Pilates I did the night before... or is it because my lower back feels heavier due to humidity... or should I just blame it on age and endure it... I'm 고민 (worried/conflicted).