The hip joint is formed between the round ball on the top end of your thigh bone (head of femur) and the socket in your pelvis (acetabulum). These joint surfaces are normally covered in smooth cartilage and the joint is surrounded and supported by soft tissues including ligaments, tendons and muscles.
OpenStax College, CC BY 3.0, via Wikimedia Commons
In older people who have not had an injury the most common cause of hip pain is arthritis.
It is not common but young adults (people around 20 to 40 years of age) can sometimes develop hip pain without arthritis or obvious provoking injury. This could be as simple as a pain coming from a muscle, tendon or other soft tissue.
Simple activity modification, over the counter pain relief and time will often help hip pain to settle. Check with your Pharmacist or GP if you are unsure whether over the counter pain relief is suitable for you.