Sudden body pain, sore throat, and weakness without cold symptoms may be due to a viral infection or early throat infection. Since you have celiac disease and take thyroxine, it is important to avoid self-medication and choose medicines carefully. Take adequate rest, stay well hydrated, and eat light, gluten-free food to support recovery. If symptoms persist or worsen, or if you develop a fever or difficulty swallowing, it is advisable to consult a doctor for proper evaluation and safe treatment.