Frequent dizziness when standing is a significant symptoms. It could be that he simply needs to drink more water, or he could have an issue with his heart. Consider getting him a filter water bottle (if he doesn't like to drink tap water) so that he can drink at least 4 ounces or so every hour or so.
If he is dehydrated, then this may be the source of his symptoms.
If he is taking medication for ADD, this could cause some stomach irritability.
His weight is good, for his age and height.
They will see him at the health department.
There are a lot of health departments that came up in search for that zip code. Here is the first one: http://www.isanticountypublichealth.org/
He seriously needs to be seen, the two symptoms together (even the dizziness alone) calls for evaluation. Lets hope it is simple dehydration, but if it is not the serious causes such as a heart problem, blood pressure problem, endocrine problem need to be ruled out.
Let me know what questions you have. If that health department is not close to you, you may do a google search for health dept 55069 in the Google search engine and it brings up all the health dept clinics on a map in that area. It is possible that the pediatric or teen clinic is not open every day at every health clinic so you may have to call and double check before you go in.
Also, please know that these clinics are federally and state funded so not as much money goes into the furniture and that sort of thing, but the doctors and nurses are well trained, and often the local medical colleges do a lot of their clinical work through the clinics, which means that there is an experience clinician over seeing everything as well as the resident, if you happen to get a resident or student. This is a good thing in my opinion, because they will be more aware of the newest treatments and any diagnosis is double checked, etc.