I had this agonising, toothache-type calf pain for over 2 years and was told it was too tight calf muscles, shin splints, stress fracture or a possible blood clot (sent to A&E twice). NHS and private consultant plus 4 different physiotherapists could not help. One very clever physio realised what the problem was and located the responsible tendon, but then could only offer massage and temporary relief.
What stopped the pain and changed my life was a visit to a physiotherapy clinic who carry out computer gait analysis. The results, coupled with the physio report, showed exactly what the stress factors were (and the fact one leg is slightly shorter than the other). I was provided with custom made orthotics and recommended to ditch sliders and slippers in favour of footwear that provides good support for the whole foot. I have 3 pairs in indoor sandals, gardening boots, and outdoor shoes.
Within a couple of days I was completely pain free and thanking the universe for such technology!