Possible reasons for your recent discomfort:
1) Weight gain = swollen feet = shoes feeling tight
2) Being on your feet all day = swollen feet = shoes feeling tight
3) Your socks are too thick for that shoe. Try thinner socks.
4) Improper storage of shoes. Shoe Trees should be inserted into the shoes to maintain their shape.
5) Lack of regular conditioning of the leather. Leather should be conditioned periodically (once per month or two) to maintain overall leather health and elasticity.
6) Foot injuries can affect sizing
7) A combination of above
Maintain your leather.
Rotate your shoes. Any shoes not worn for 1 year should be donated or passed on.
To revive a neglected pair of shoes, apply leather lotiion/conditioner with hand, working the leather. let sit 1 hr, brush, buff. repeate if necessary.
Get those shoes back on yor feet. You may have to wear them for 30 minutes before leaving home. The heat & moisture from your foot will aid to soften the leather out of its stiffness somewhat.
Wear the appropriate thickness of socks that best serve those shoes.
Also, as I understand it, certain things on our bodies continue to grow throughout our lifetime.
Head, ears, nose and feet all grow even in adulthood.
This is why women dread the old saying that sums them up from youth to older ages:
'From Class and Clothes To Ass and Nose.'
Hope this helps and welcome back to the forum.