Brief Answer:
Needs workup

Detailed Answer:
Hello

My name is Dr Muhammad Ali Rauf & i will look into your problem.

I have gone through your query and would try to help you in the best possible way. As you have mentioned multiple issues so i would discuss each one separately for your ease:

1. Pain behind knee:
There are multiple causes if pain. If it ha started suddenly then most probably it could be due to some trauma or injury. If it has developed gradually then most common cause is baker's cyst. In this a swelling appears behind knee in popliteal fossa which causes pain. If it is the case then a surgeon will examine it thoroughly and will decide further workup. It is not something for which you need to worry at the moment. Only problem it causes is pain and restricted movement.

2. Fainting/dizziness:

a. Postprandial Hypotension:
After meal high quantity of blood is required in G.I tract for food digestion. For this heart must use strength to supply blood to essential organs. Now in some people heart is not able to push blood effectively as a result vitals organs including brain does not get enough blood and as a result dizziness occurs. It is also associated with other conditions like hypertension, diabetes, drug induced or other chronic illness

b. In some cases it may also occurs when blood vessels in your body dilates, as a result blood pools in dependent parts of the body like legs. In this case brain does not gets adequate oxygenation so dizziness and fainting occurs. It is termed as "Vasovagal Syncope". A sitting with medical specialist will help confirming this condition. It is treatable will lifestyle modification & medication like beta blockers.

c. Another cause which is also common is allergic response to particular food. Sometimes body gets allergic to particular food so when one eats that particular food then symptoms like dizziness, rash and/or itch may appear.

3. Pain in calf muscles:
This could be fibromyalgia. In this condition due to causes like stress, sleep problem or anxiety there is pain in muscles of the body which could be specific to one particular group. It can be treated promptly by taking antidepressants & analgesics. If i were your treating doctor then i would have advised ibuprofen & duloxetine. Duloxetine is a prescription drug which you can get from a local doctor.

Conclusion:
You can wait until your get your insurance but you need to take extra care. e.g Don't perform any activity immediately after eating food so that you won't fall down and cause damage to brain or other parts of the body. If a patient comes to my clinic with such problems then apart from medical workup i will give following home care remedy for dizziness after food:
> Avoid skipping meals specially breakfast.
> Eat dinner at least 2 hrs before bedtime.
> Stay well hydrated by drinking adequate fluids like water.
> Avoid alcohol.
> Avoid doing sternous activity immediately after taking meal.
> Avoid food that particularly causes such spells. In you case food with higher salt content.
> take a walk in the evening. It will relieve stress and will make you fresh.

Hope I have answered your query. If you have any further questions I will be happy to help if not then don't forget to close the discussion and rate it.
Wishing you good health !!

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