Keep asking the same questions
Clients aren't always going to volunteer information on injuries, concerns, or problems.
If you have a client with tight shoulders, ask every session - how are the shoulders? Hip pain? How is the hip?
You need to keep probing - gently but firmly and regularly - in order to stay on top of your client's progress. If you let it slide, you're potentially showing you don't care, and you're missing a chance to monitor the results of your training. You might find a need for extra mobility drills or changing sets or reps or exercises. These are things that can't wait, and you need the feedback. Make sure you pursue it regularly.