Based on your description, the symptoms do not strongly suggest cancer. Pain that starts in the upper arm and radiates to the thumb and index finger is more commonly related to nerve irritation from the neck (cervical radiculopathy), especially involving the C6 nerve root. This can also cause burning sensation in the shoulder or arm.
The mild temperature you mentioned (98.9°F) is actually within the normal body temperature range, so it is usually not considered fever medically.
Pain in the upper breast along with arm/shoulder discomfort can sometimes occur due to:
• Muscle strain or nerve compression from the neck
• Costochondritis (inflammation of chest wall joints)
• Hormonal breast pain (mastalgia)
A bruise appearing at the painful site is usually due to minor capillary injury or unnoticed pressure/trauma, not a typical sign of breast cancer.
Breast cancer usually presents with symptoms like:
• A painless hard lump in the breast
• Skin dimpling or peau-d’orange appearance
• Nipple retraction or abnormal discharge
• Persistent swelling of lymph nodes in the armpit
From what you described, these classic warning signs are not mentioned.
Next Steps
To be safe and get clarity, you can consider the following:
• Clinical breast examination by a doctor
• Breast ultrasound (preferred test in women under 40)
• If arm pain persists → X-ray or MRI of cervical spine to rule out nerve compression
• Basic tests like CBC, ESR or
CRP if symptoms continue
If the pain is nerve-related, treatment usually involves posture correction, physiotherapy, and anti-inflammatory medicines, which improve symptoms gradually.
Health Tips
• Avoid long periods of mobile/laptop use with neck bent forward.
• Use a proper pillow and good neck posture during sleep.
• Gentle neck and shoulder stretching exercises can reduce nerve irritation.
• Monitor for any new breast lump, persistent swelling, or nipple discharge—if these appear, seek evaluation promptly.
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If you want, you can also describe whether you feel any lump in the breast or underarm, and I can guide you further about the most appropriate tests and treatment through an online consultation.