What could be causing severe arm pain that progressed from bone pain to muscle soreness and now a burning sensation in my hand, along with a hard lymph node under my arm?

Urgent Evaluation Required for Possible Malignancy or Serious Neurologic Pathology

You need immediate medical evaluation—this combination of progressive arm pain, burning hand sensation, and a hard axillary lymph node raises serious concern for malignancy with nerve involvement or cervical spine pathology causing myelopathy.

Critical Red Flags Present

Your symptom constellation is concerning for several serious conditions:

• Hard lymph node in the axilla is particularly worrisome and may indicate lymphoma, metastatic cancer, or other malignancy 1
• Progressive pain pattern (bone pain → muscle soreness → burning hand) suggests evolving neurologic compromise, potentially from cervical myelopathy or nerve compression 2
• Burning dysesthesia in the hand can indicate acute neurologic deficits requiring urgent imaging 2

Most Likely Serious Diagnoses to Rule Out

Malignancy with Nerve Involvement

• Lymphoma or metastatic disease can present with hard lymph nodes and cause nerve compression or infiltration 1
• The progression from deep bone pain to burning neuropathic pain suggests possible tumor involvement of neural structures
• This requires urgent evaluation with imaging and possible lymph node biopsy

Cervical Myelopathy

• Acute cervical myelopathy can present with arm burning dysesthesia and progressive symptoms 2
• Even without obvious risk factors, congenital cervical stenosis can cause acute neurologic symptoms 2
• Early diagnosis is essential to prevent permanent neurologic deficits 2

Brachial Plexopathy

• Progressive arm pain with burning hand sensations may indicate brachial plexus involvement
• Can be caused by tumor compression, radiation injury, or inflammatory processes

Immediate Diagnostic Approach

Step 1: Physical examination focusing on:

• Characteristics of the lymph node (size, mobility, texture, tenderness)
• Neurologic examination of the entire upper extremity (strength, sensation, reflexes)
• Assessment for other lymphadenopathy or systemic signs

Step 2: Initial imaging:

• Plain radiographs of the arm to rule out bony lesions or fractures 1, 3
• Cervical spine MRI without contrast if any neurologic deficits are present to evaluate for myelopathy 2

Step 3: Lymph node evaluation:

• The hard lymph node requires tissue diagnosis if imaging suggests malignancy
• Consider ultrasound-guided biopsy or excisional biopsy 1

Step 4: Advanced imaging if radiographs are normal:

• MRI of the arm without IV contrast to evaluate for soft tissue masses, nerve involvement, or bone marrow pathology 3
• MRI is superior for detecting occult malignancy and nerve pathology 3

Less Serious But Possible Diagnoses

Complex Regional Pain Syndrome

• Can cause burning pain and has characteristic bone scan patterns 1
• However, the hard lymph node makes this less likely as the primary diagnosis

Inflammatory Arthritis

• Can cause joint pain and lymphadenopathy 1
• The burning quality and hard lymph node make this less likely

Chronic Neuropathic Pain

• Burning sensations are characteristic of neuropathic pain 4
• However, this doesn't explain the hard lymph node or the progressive nature from bone pain

Critical Pitfalls to Avoid

• Do not dismiss the hard lymph node—this is the most concerning finding and requires definitive evaluation 1
• Do not delay imaging if neurologic symptoms are present—cervical myelopathy requires urgent diagnosis to prevent permanent deficits 2
• Do not assume this is musculoskeletal pain—the progression and associated lymphadenopathy suggest systemic disease 5
• Do not start with ultrasound alone—while useful for superficial structures, MRI is needed to evaluate for deep pathology and malignancy 3

Timeline for Action

Within 24-48 hours:

• Complete physical examination with detailed neurologic assessment
• Plain radiographs of the affected arm
• Cervical spine MRI if any neurologic deficits present

Within 1 week:

• MRI of the arm if radiographs are normal
• Lymph node biopsy or fine needle aspiration if imaging suggests malignancy
• Hematology/oncology consultation if malignancy suspected