15 years post breast reduction - breast pain feels like skin tearing. What could cause this?

This sounds like neuropathic pain, for example an injured, stretched nerve or one that is entrapped in scar tissue like a neuroma. It is occurring 15 years after surgery, and is localized, so it sounds like a branch of the intercostal nerve is being entrapped or stretched, and so is painful when the breast moves.
A physical exam may elicit a Tinel's sign along the course of the nerve, helping to locate the source.
An ultrasound, or MRI may show some pathology in the breast that is causing or related to it. One assumes you have had a mammogram to rule out breast cancer.
Your plastic surgeon can examine you and help sort out the various causes and possible treatment based on the findings.

This far out from surgery it's difficult to say what may be occurring without an exam and more information. You may have simply strained the area. If that is the case then it should improve with rest. If your situation remains or worsens I encourage you to visit with your surgeon for an evaluation.

Hello dear. It could be irritation or tension in scar tissue, trapped nerves, or local inflammation related to the previous surgery. It could also be post-surgical neuritis (delayed onset nerve pain). Wearing a compression bra helps because it limits movement of the affected tissue. An evaluation is necessary to review the area. You can contact us at 829-554-6062.

Breast reduction 15 years ago with good healing, new onset of sharp, snapping or tearing pain near an old scar, no visible changes, and pain triggered by movement—there are a few possibilities that might explain what you’re feeling:
1. Scar Tissue (Adhesions or Nerve Entrapment)
Over time, scar tissue can thicken, harden, or contract. This may irritate or trap surrounding nerves, especially near incision lines. The "snapping" or "tearing" sensation could be:
• A stretched nerve ending that’s being pulled or compressed.
• Adhesions between skin and deeper tissues moving awkwardly with your breast motion.
2. Fat Necrosis or Oil Cyst
Though these are more common earlier after surgery, they can sometimes develop later or go unnoticed:
• Fat necrosis can form firm, sometimes painful lumps.
• Oil cysts may form and stretch surrounding tissue, especially with movement.
3. Delayed Onset Nerve Pain
Occasionally, sensory nerves affected during surgery can regenerate abnormally or become hypersensitive, even years later. This may produce:
• Sharp, electric, or tearing-like sensations.
• No external signs but consistent pain with motion.
4. Muscle or Connective Tissue Strain
Even though you say it’s not related to arm movement, underlying pectoral or fascia strain can refer pain to the breast area, especially near old surgical planes where tissues were altered.
5. Hormonal or Skin Changes
Skin thinning or connective tissue changes with age or hormonal shifts could make previously quiet scars more reactive or sensitive.
6. Other Less Common Possibilities
• Small herniation of glandular or fatty tissue through a weak spot in the old surgical area
• Subclinical infection or inflammation rare but not impossible
• Recurrent cyst or benign growth
When to See a Doctor
You're doing the right thing by planning to see a provider. You should definitely go sooner if:
• The pain worsens or spreads
• You notice swelling, warmth, or redness
• A lump forms
• You develop fever or feel generally unwell
Your provider might recommend
• A breast ultrasound or mammogram (especially to rule out deeper issues)
• Possibly an MRI for better soft tissue visualization
• A review by a plastic surgeon if surgical tissues need to be evaluated
In the meantime, using a compression bra and avoiding excess breast motion as you're doing are solid steps. Avoiding underwire may also help if there's nerve involvement.

Breast pain is common and often there is no identifyable cause.
If your of mammogram age then that would be a start.
Best
Mats Hagstrom MD