Is lower back pain after sex due to kidney deficiency?

Patient's question:

Patient Gender: Female
Patient Age: 27 (currently 46)
Lower back pain after intercourse, is it kidney deficiency?
Recent medical history and treatment outcomes: None

Doctor's answer:

Pain in the lower back after male sexual activity is not due to kidney deficiency. During sexual activity, the lower back muscles are engaged, and this type of pain is similar to abdominal pain experienced during sit-ups—it is a result of local muscle strain or "overexertion." In short, it is caused by a lack of physical endurance or insufficient activity.