Hi, i'm 23 and have had a headache for 10 days. moderate pain, feels like all pressure all over, inc cheeks, top teeth & forehead. is this serious?

Need to be seen: It may be related to a sinus infection given that cheeks, teeth and forehead involved. Those are all areas associated with sinus cavities. When there is congestion in nasal passages and sinuses cannot drain properly pressure will build up in the cavities which causes pain. Relieving the pressure will often relieve the pain and antibiotics may or may not be needed. See provider/ inbox consult.

Possibly sinus: Sinusitis is characterised by frontal headache, blocked, or runny nose, facial tenderness and possibly fever. It is usually viral and self limiting ... see http://patient.info/health/acute-sinusitis for more details. Simple analgesics such as Paracetamol or Ibuprofen are usually sufficient. See your Dr if unwell, or worsening pain, or if pain persisting for more than 7 days.

Sinus? Teeth: The short description you give sounds like sinus pain. You might like to try some decongestants which you can buy from a pharmacist. They can also advise you on pain relief (e.g. paracetamol +/- ibuprofen). Another possibility is pain coming from your teeth - if you think you could have a cavity or dental infection then a trip to the dentist is in order.