Insect bite - stiff neck, shoulder and lymph node pain.....

A few months ago I noticed what it looks like an insect bite on my left breast, a small red painful nodule on my skin.  Soon after I started experiencing pain below my arm pit, stiff neck.  This pain moved across by back to my right side, which has now taken residence for the past 2 months - stiff neck, can't extend my right arm upwards without pain, pain in shoulder joints, pain below my right arm, lethargy, etc.....

My doctors prescribed azithromycin anti-biotics for 1 week, but it did not relieve my symptoms.  I take Gabapentin/Neurontin and Lyrica for diabetic degenerative peripheral neuropathy, which some times has reduced some of this other pain I am experiencing, but not the inflamation (inflammation).

I do have, what it appears to be, brown recluse spiders in my yard,, and I have even found a couple of spiders inside my bedroom and do not how they got inside.  I do not know if this spider is the culprit of one of my debilitating conditions, could be another insect while sitting by the marshes and woods while my husband is fishing......

My stiff neck, pain below and above the shoulders and arms, and painful lymph nodes may or may not be related to this insect bite.   What could this be caused from.  What should I ask my doctor to test me for.  How can it be effectively treated?