Plenty of big problems and small problems in physics to be solved. My father was a research physicist who sat on the international committee for defining tempe

Plenty of big problems and small problems in physics to be solved. My father was a research physicist who sat on the international committee for defining temperature, his little contribution to the world was to improve the low temperature model of measurement to make it 50000 times more accurate... and still had a lot of room for improvement. An area still under active research. At the broad scale we need to understand the mysteries of dark energy/matter, develop a quantum understanding of gravity, etc..... One problem that's happened is a lot of the physics in the early 20th century didn't have any experimental proof till late 20th century, physics pushes at our technological limits and has to wait patiently :)