When trying to ping and get records of dns domain, I get unexplained error

I am very new to golang, and I am using the dns library from github.com/miekg/dns to do this. I'm just trying the library out. I first call upon google.com in a loop which calls the domain 10 times, then averages the 10 pings. It does this with the defined client IP being localhost on port 53.

When I do this out of the loop however, with my client IP being the same localhost on port 53, it gives the error of "connection refused". Same thing happens when I set my client IP to be 192.168.1.21, which has the same value of localhost. HOWEVER, when I set my client IP to be 192.168.1.32, which is the IP of my raspberry pi on my network, it works! How come it is able to make the DNS connection in that loop, but not outside the loop? How come it is able to make the connection outside the loop with a IP different from the device I am running the script on? Here is my code:

package main
import (
"fmt"
"github.com/miekg/dns"
"math"
)
func main() {
m := new(dns.Msg)
m.SetQuestion(dns.Fqdn("google.com"), dns.TypeA)
c := new(dns.Client)
var individualPings float64
//looping over for 10 times and prints each one while also adding it to variable individualPings to get average at the end
for i := 1; i <= 10; i++ {
_, rtt, _ := c.Exchange(m, "localhost:53")
fmt.Printf("%vth ping is %v\n", i, rtt)
individualPings = individualPings + (float64(rtt))
}
pingAverage := individualPings / 10
fmt.Print("\nThe ping average was: ", math.Round(pingAverage)/1000, "ms\n")
//tries to do the same thing
_, rtt, err := c.Exchange(m, "localhost:53")
if err != nil {
panic(err)
}
print(rtt)
//tries to do the same thing but client is defined with it's ipv4 instead of just "localhost"
in, rtt, err := c.Exchange(m, "192.168.1.21:53")
if err != nil {
panic(err)
}
fmt.Println(in.Answer)
fmt.Println(rtt, "\n\n")
//tries to do the same thing but client is defined to be my raspberry pi instead of the device the script is running on. This works. Of course the program panics before it reaches this part, however I've tested it without the clutter above and it works
in, rtt, err = c.Exchange(m, "192.168.1.32:53")
if err != nil {
panic(err)
}
for record := range in.Answer {
fmt.Println(in.Answer[record])
fmt.Print("\t", rtt)
}
}

Thanks

======================================

First, in order to do a DNS query on a specific IP and port there need to be actually a DNS server running there and responding to queries. There is no guarantee that such a DNS server is on localhost:53 or 192.168.1.21:53. So first check with tools like dig that you actually do get a response from a DNS server at a specific ip:port in the first place before asking why you get errors in your program.

> I first call upon google.com in a loop which calls the domain 10 times, then averages the 10 pings. It does this with the defined client IP being localhost on port 53.<br>
> When I do this out of the loop however, with my client IP being the same localhost on port 53, it gives the error of "connection refused".

It likely gives the same error inside the loop. Only, inside the loop you simply don't handle the error and thus nothing gets reported. Compare your code inside the loop (no error handling):

    _, rtt, _ := c.Exchange(m, "localhost:53")

with the code outside the loop (with error handling)

_, rtt, err := c.Exchange(m, "localhost:53")
if err != nil {
panic(err)
}