I agree w/ Quadsweep; it's probably "plantar fasciitis". The classic presentation is worst in AM upon arising, improves with walking around, warming up.
Fasciitis is usually a misnomer, IMO. The primary problem is usually NOT an inflammatory one, but rather a degenerative one (caused by macro or micro trauma). Most orthopods and podiatrists will treat it w/ cortisone inj, which may temporarily help if there is a secondary inflammation; in the long run, however, cortisone is catabolic and weakens the tissues. Orthotics sometimes help.
Sometimes there's a co-existing "heel spur" on X-ray: this is NOT the cause of the pain, it's just the body trying to stabilize the ligament attachment at the calcaneous (heel bone) by laying down new bone (osteophytes: happens in the spine, and other joints, too).
Prolotherapy is the treatment of choice IMHO. Of course, I'm biased.
buffdoc