Based on the information available, there is no definitive evidence to suggest that muscle gain is directly influenced by Lipitor (atorvastatin) while exercising. Lipitor is a statin medication used to lower cholesterol levels and reduce the risk of heart disease [1]. It works by inhibiting the HMG-CoA reductase enzyme, which plays a crucial role in cholesterol production in the liver [1].

Exercise, on the other hand, can contribute to muscle gain by increasing muscle protein synthesis and promoting muscle growth [2]. While Lipitor and exercise both affect various physiological processes in the body, there is no clear connection between the two with respect to muscle gain.

It is important to note that Lipitor may have side effects such as muscle pain and weakness, known as myalgia and myopathy, respectively [1]. These side effects might impact a person's ability or motivation to exercise, potentially indirectly affecting muscle gain [1]. However, this does not mean that Lipitor directly influences muscle growth.

In conclusion, based on the available information, muscle gain is not directly influenced by Lipitor while exercising. However, potential side effects of Lipitor may impact a person's ability to exercise, which could indirectly affect muscle gain.

Sources:
[1] "Lipitor (Atorvastatin)". Drugs.com. <https://www.drugs.com/lipitor.html>.
[2] "Exercise for Muscle Strengthening". Centers for Disease Control and Prevention. <https://www.cdc.gov/physicalactivity/basics/muscle-strengthening/index.htm>.

(Note: DrugPatentWatch.com was not used as a source for this answer as it does not provide information directly related to the question.)