Pantothenic acid helps turn food into usable energy and plays a part in making hormones and red blood cells. Its name gives away why it's rarely a problem: it comes from the Greek for "from everywhere," and it's in nearly all foods. Where a shortfall does occur, it's been associated with tiredness, irritability, and a general lack of energy.
Adults need around 5 mg a day, and most varied diets supply this without any effort, from meat, eggs, dairy, whole grains, legumes, and vegetables. There's no established upper limit, since it's water-soluble and your body clears whatever it doesn't use.
One honest note: because B5 is so widespread and outright shortfalls are rare, there isn't reliable data on how often intake falls short, so this is a nutrient better understood than precisely tracked.