First of all, take a dermatologist's opinion regarding any superficial corns in the heel. Lately I've been see many cases coming with heel pain and actually have corn and no Orthopaedic issues. Secondly, more history about the heel pain is required. If the heel pain is severe in the mornings when you wake up and subsides after a few steps, it could be Plantar fascitis which is one of the most common heel pain issues. The other thing could be Retrocalcaneal bursitis which is behind the heel. Both these problems usually don't cause bruising.
Next Steps
1. dermatologists opinion
2. in case there is no sling Condition, start calf stretching exercises as a part of physio to treat plantart Fascitis or Retrocalcaneal bursitis
3. wear a shie raise, a soft heel within your shoes
Health Tips
Do not Massage and dont neglect