Massachusetts can be looked at in three general areas. Locals may argue otherwise as we have the north shore, south shore, Cape Cod, and the New Bedford area that encompasses the larger Boston area.
Western Mass (ain't no one out that way 'cept for some sheep )
Central Masschusetts
Hall of Comics - https://thehallofcomics.com/ (My LCS)
122 Turnpike Rd, Westborough, MA
That's Entertainment- https://thatse.com/
244 Park Ave, Worcester, MA
Bedrock Comics - http://www.bedrock-comics.com/
371 Worcester Rd, Framingham, MA
Rubber Chicken Comics - http://www.rubberchickencomics.com/
15 N Main St # A4, Bellingham, MA
I can personally recommend the first three and have heard great things about rubber chicken.
Boston area
The Outer Limits - https://eouterlimits.com/
437 MOODY ST. WALTHAM, MA