If over-the-counter vitamin d causes headaches at varying doses, should i be on a prescription pill? where do you get vitamin d without additives?

No: You should not be on prescription medication unless you have a blood test showing that your levels are low.

Examine ingredients: Although nutritional supplements are chosen primarily for their active ingredients, the other ingredients (excipients) needed to make the tablet, capsule or liquid are just as important to those concerned about their health. I use and recommend carlson vitamin d drops as a highly effective product free of excipients that might cause adverse effects.