Could gabapentin cause a serious muscle pain ?

No: Itcan treat muscle pain not cause it.

Can cause myalgias: In about 3-5% of patients myalgias or muscle pains are reported with varying severity. There are also slightly different forms of gabapentin nowadays so it may depend a bit on whether you are talking about Neurontin, Gralise, or Horizant being the brand names in common use as to the severity or prevalence of symptoms. If you have more questions: www.healthtap.com/drsaghafi