Is lying always a sin? If someone asks me, “How are you?”, and I answer, “I’m fine,” but really am not, did I just commit a sin? Or when someone makes a dish of food for me and asks, “How was it?”, and I say it was great, but it wasn’t. Are these sins?
No one is obliged to disclose everything that he or she knows or feels. To your first question, “I’ve had better days” would be truthful, but you do not have to get into all the details that prompted that response. Likewise to your second question, instead of saying “It was great,” can’t you say, “It’s an unusual taste that I am still processing”?
No one being tortured is obliged to tell the whole truth. As a priest who hears confessions, I cannot be obliged to reveal the details of what a specific person has confessed.