It isn't your imagination—bodies often swell slightly throughout the day, especially around the ribcage. For women 55+, this can make a band that fit perfectly in the morning feel two sizes too small by evening.
Perimenopause and menopause can lead to body composition shifts and weight gain, often resulting in an increase in breast size—sometimes by two cup sizes or more. If your bra is cutting into your skin or causing chafing, you may have changed sizes without realizing it. mature bras tight
The Midday Squeeze: Why Your Bra Feels Tight (and How to Fix It) mature bras tight