Sore throat when swallowing saliva, pain in the left back of the head
Throat pain when swallowing saliva accompanied by left posterior headache may be caused by insufficient water intake, high mental stress, tonsillitis, pharyngitis, or herpangina. Treatment options include proper hydration, emotional regulation, and medication. It is recommended to visit a hospital for accurate diagnosis and follow medical advice accordingly. The analysis is as follows:

1. Insufficient water intake: Inadequate hydration may lead to a dry throat, resulting in throat pain when swallowing saliva, and in severe cases, may cause pain in the left posterior part of the head. It is advisable to drink water promptly and maintain a humid environment to help relieve discomfort.
2. High mental stress: Short-term excessive tension, anxiety, or stress may affect hormonal balance, leading to symptoms such as dryness, itching, and pain in the throat. Swallowing saliva may worsen discomfort and trigger blood vessel spasms, causing headaches—sometimes localized to the left posterior head. In such cases, it's important to regulate emotions, relax, and ensure adequate rest for the brain.
3. Tonsillitis: Usually caused by infection, this condition primarily presents with sore throat and often accompanies headache and dry throat. Complications such as pain in the back of the head after swallowing saliva may occur. Treatment may include medications such as Pudilan Anti-inflammatory Oral Liquid, Amoxicillin Capsules, or Roxithromycin Tablets, as prescribed by a physician.
4. Pharyngitis: Typically caused by viral infection, symptoms include burning sensation, itching, and swelling or pain in the throat. Severe cases may present systemic symptoms like headache and fever, as well as pain in the back of the head when swallowing saliva. Under medical guidance, medications such as Compound Sarcandra Glabra Lozenges, Lanqin Oral Liquid, or Yinhuang Throat Lozenges may be used.
5. Herpangina: Usually caused by viral infection, clinical manifestations include fever, sore throat, and vesicles in the pharyngeal area, and may also present the aforementioned symptoms. Patients should take medications such as Ibuprofen Sustained-Release Capsules, Qingkailing Injection, or Ribavirin Tablets under a doctor’s recommendation to aid recovery.
In addition, throat pain when swallowing saliva along with left posterior headache could also be caused by cervical spondylosis. Patients are advised to seek timely medical attention if they experience any bodily discomfort.