For colds, I second Zelda's suggestions, especially garlic (but my husband, having just been shown the Bun-bun vs. snake thread, commented "some people apparently worship rattlers.") If you have a lot of mucus you may wish to avoid tomato products in addition to dairy.
For chronic headaches, see DixieGal's recommendations, but I would also add that many headaches are in fact due to clenched jaw, so seeing a dentist for tooth occlusion problems (causing grinding) might help. Alternatively, another common cause of my headaches is inflamed turbinates (in the sinuses). Pseudoephedrine helps (the imitation no-signature-required stuff does nothing for me), or Afrin nasal spray (but be careful how often you use it, as it can cause a dependency).
I also found, after being so advised by my doctor, that taking a multivitamin every day, plus 500mg vitamin C three times a day, and three capsules of echinacea twice a day really helped build my immune system back up.
For tension neck/eye/head aches, I recommend either/both hot tub soaking and yoga.
In particular, there is a common yoga warm-up that involves letting your head hang forward, then gently rolling it back and forth. I find that it really helps my neck muscle tension problems. For eye/head aches, it might be worthwhile to see if you're also experiencing inflamed sinuses, e.g. due to allergies.
I am not a medical professional. I'm just passing along what has worked for me in the past with similar ailments.