Hip muscle left sore and pain. Span?

My mother has a hip replaced The Exeter cemented femoral hip (Stryker) 14 years know and was going well until past 3 months. The surgeon (from UK relocated to india Bangalore and did a great job and the surgery was 100% text book ideal outcome.) Current Scenario - She is complaining of sever pain and finds it painful. X-rays - show a normal result. No findings. Or dislocation. She seems to be good with Tremadol (calpol T) but gets back to pain once subsided. Challenge- She is constantly screaming and crying due to pain (constant cries ) Question- does anyone here help to address if Stryker (Exeter) has a limitation of life span ? What is the next step as surgeon rules out any hip dislocation just ask her to go on pain killer. Her pain seems SEVERE and constantly screaming ! She never ever has been so bad. She was always functional and doing her own cooking and all actions until 90 days . But now finds it unbearable. Any direction/advice greatly appreciated can consult u