Here the retro calcaneal pain could be due to couple of resion. It can be due to inflammation at local area in bone or soft tissue, it can be due to calcaneal bone extra growth at painful level, it can be calcaneal bursitis. How ever the conformation can be done with ct scan or MRI scan to know the proper cause. Now if its just over use inflamation then with physio therapy and cold pack usage it can be improve well. If it is calcaneal bone growth or bursitis then initially can be treated with physio therapy along with alternate hot and cold water use. Along with this one should also use soft foot wear like micro cellular pollimer material. One can also use silicone sole for their foot wear for extra softness. Suppose if it is not yet over with all above steps then there is hydrocortisone injection can also be given at local painful heal level. Even if it is not becoming better with this means for calcaneal bone growth you need to under go for minor surgical correction like removal of extra growth. But this treatment will be decided by your orthopedic doctor due to failure of all other primary treatment and precautions. Here you have mention you have tried with medicine but have never tried with physio therapy treatment, soft foot wear use, silicon insole use, hot and cold water use by deeping feet in it and keeping it floating so water can touch all around. So you can try with all this primary treatment steps. Along with this take simple stretching exercises with physio for your feet and heal. This will give you very good relief when it is followed all together. Take care.