It has to be a slippery slope especially for 2nd ammendment supporters. You don't want to fight for one freedom by losing another.
on the other hand it only stands to reason that the computer/phone revolution be used by law enforcement.
The general (VERY general, there are lots of ins and outs) state of the law is that electronic content is treated as "papers," under the Fourth Amendment, i.e., the government generally needs a court order (typically a search warrant) to search or seize them.
Places you can get tripped up generally revolve around who is the actual owner of the data: you or the company? In the case of google, Facebook, &c., the data belongs to the company, which can consent to give it to the government (or anybody else).
And of course in this case none of that applies, because as I said, deaders don't have Constitutional rights.
As far as the Second Amendment goes, there are two main threads of interpretation. Each presents different challenges.
Some people read the second part, "the Right of the People to keep and bear Arms, shall not be infringed." as an individual right of everyone to keep and bear arms. Others say that the first part, "A well regulated Militia, being necessary to the Security of a free State," as meaning that the only thing that is protected is militia weapons.
Problem with the second interpretation is that a militia is light infantry, and these days that means that people would be allowed to own automatic rifles, grenades and grenade launchers, and light rocket launchers. Not ideal.
Another thread of thought, and the one I hold with, is that self-defense is a natural right which precedes all positive (written) law, and that depriving someone of the means to effectively exercise a right is the same as depriving them of the right. Therefore, while the government can impose various limitations on number and type of weapons, it cannot deprive you of the reasonable tools necessary for self defense, which means guns these days.