Plantar fasciitis is often the diagnosis when your heel gives you grief, especially early in the mornings just after getting up and when putting weight on the heel after periods of rest during the day.
Though it is called “-itis”, which means “inflammation”, this is not necessarily correct. The fascia between the heel and the ball of the foot is stressed (rather than inflamed), causing pain, so we are dealing more with a plantar fasciosis. Causes can be wrong foot wear, excessive use i.e. (jogging, ballet, long standing) but also a lack of exercise, a very high or low arch, or tight calf muscles/ tight achilles.
One possible home remedy may be softening the foot in warm water with Epsom salt (including the calf muscles!) and then stretch the fascia carefully by rolling the foot over a golf ball or tennis ball.
Chinese medicine (CM) considers sharp pain to be caused by Blood Stasis and Blood deficiency. Contraction of muscles (usually the calf muscles) is interpreted as Spleen deficiency, a contraction of tendons/fascia is caused by Liver Blood deficiency (as usual, Liver and Spleen mentioned here are not the Western medicine organs, but rather CM placeholders for specific CM pathologies).