The pain on back of the head can probably due to sinusitis. Avoid foods( refrigerated foods) and environment( dust, agarbatti) that trigger your sinusitis. Breathless is also due to the sinusitis as it blocks your sinuses in the nose making it difficult to breath.
Next Steps
it is not an emergency condition but do consult an ENT physician for appropriate treatment.
Health Tips
continue your bp medications in case ur taking them