Are there any good 'one stop shop' online marketing companies that can help a Physical Therapy office reach/be in front of potential customers? Typical customer includes people with neck/back pain, sports injuries and other joint and muscle problems?
What you're looking for, primarily, is local SEO. There are plenty of web marketing companies that offer local SEO services, including my own: Pole Position Marketing. Local SEO will help make sure you have all the right local signals in place, but you also need a strategy beyond that, which should include organic SEO, social media and a content strategy.