Trauma such as a fracture, dislocation, or soft tissue damage is one cause of sudden hip pain. In most cases, however, hip pain tends to be a chronic problem, which could be due to:

Arthritis

Arthritis is a joint disease that comes in many forms, causing chronic pain, stiffness, and increasing weakness. Osteoarthritis is the most common type of arthritis, resulting from years of wear and tear and the loss of protective cartilage from the bones in your joints. The inflammatory autoimmune disorder rheumatoid arthritis is the second most common form of the disease.

Bursitis

Bursae are sacs containing liquid inside your joints that help prevent pressure and friction. Sometimes the bursae develop inflammation, causing pain. Trochanteric bursitis on the outside of the hip is a frequent cause of hip pain that can make it impossible to lie on the affected hip.

Labral Tear

Your hip consists of a ball-shape at the top of your femur (thigh bone) called the femoral head and a socket called the acetabulum. Around the edge of the acetabulum is a ring of cartilage – the labrum – that helps keep the femoral head in its socket. Labral tears sometimes occur from acute injuries but are often the result of repetitive strain.

Femoroacetabular Impingement (FAI)

Typically, the ball of your femur and the socket fit together seamlessly. Some people have abnormal bone growth in the hip during early childhood, which causes the ball, socket, or both to shape incorrectly. As a result, the bones rub against each other painfully when you move your hip.

Hip Dysplasia

Hip dysplasia is another condition typically present from childhood. In this case, the hip socket does not form correctly and therefore cannot cover the ball. When this occurs, your hip joint can become dislocated. If this problem goes untreated for an extended period, it can harm the nearby cartilage, resulting in a labral tear.