Flank pain when lying on your right side: what should you know?

A mattress, sleeping posture, or pressure on a tender area can irritate the muscles between the ribs, abdominal wall, or lower back. Pain that improves when you change position and can be reproduced by touch or movement is more suggestive of the body wall, although it does not prove the cause. Kidney stones can cause right flank pain that travels toward the groin or comes in waves. A kidney infection can cause pain with fever, chills, nausea, or feeling unwell. Urinary tract infection symptoms include burning or needing to urinate often.

The right side also contains abdominal organs, so note whether the pain is high under the ribs, toward the back, or lower down. The pattern and associated symptoms matter more than the sleeping position alone.

Try sleeping on the other side or on your back with a pillow supporting your knees, and avoid pressure over the painful area. Gentle daytime movement can prevent stiffness; stop if it sharply increases pain. A warm pack may help a muscular ache. Arrange a medical review if positional pain lasts, keeps returning, or affects sleep, particularly if you develop urinary changes, nausea, or fever. A clinician can examine the area and may check a urine sample.

Seek urgent care for severe or escalating pain, fever or chills, repeated vomiting, yellowing of the skin or eyes, blood in urine, or inability to pass urine. Get emergency help for fainting, confusion, severe weakness, chest pain, or breathing difficulty. Seek prompt assessment after a significant fall or blow.

Ask whether the pain pattern fits a muscle or joint problem and whether urine testing is appropriate. Share the exact area, the positions that help or worsen it, bowel and urinary changes, fever, injury, and any new medicines.