[SalesForce] Soql to count How many each pick list values for picklist field in Object

You need to use SOQL Aggregate functions. In this example i am using the COUNT() function.

Preamble
In this small example we are counting all contacts depending on the last name:

AggregateResult[] contactListAggregated = [Select count(id), LastName
                                           From Contact
                                           Group By LastName ];

for (AggregateResult entry : contactListAggregated){
    System.debug('#### Number of contacts: ' + entry.get('LastName') + ' - ' + entry.get('expr0'));
}

The result will be like this:

#### Number of contacts: Johnson - 25
#### Number of contacts: Doe - 12
#### Number of contacts: Davis - 156

You can try this code in your developer console.

Now my example:

// First we must read the data from your temp contact object
List<Temporary_contact__c> temporaryList = [Select id,Name,First_Name__c,Last_Name__c,Email__c,Contact_list__c 
                                            From Temporary_contact__c
                                            Order By createddate desc ];

// Now iterating this list with temp contacts an saving last names and emails
for(Temporary_contact__c temporary : temporaryList)
{     
    listoftemp.add(new tempcon1(temporary));
    condetails = chk.Contactdetails(temporary.Xmldata__c);
    conlstemail.add(condetails.email);
    conlstname.add(condetails.lastname); 
}

// Now we will use aggregate function count to get the number or related contacts
AggregateResult[] contactlistAggregated = [Select count(id), LastName
                                           From Contact
                                           Where LastName IN :conlstname
                                           Or (email != null and email IN :conlstemail)
                                           Group By LastName ];

// Iterating temp list again and compare the last names
for(Temporary_contact__c temporary : temporaryList)
{  
    for (AggregateResult entry : contactlistAggregated){

        if(entry.get('LastName') == temporary.Last_Name__c)
        {
            // Here we are saving the number of related contacts to the temp list
            temporary.Contact_list__c = string.ValueOf(entry.get('expr0'));
        }
    }
}

I think that the issue is the where clause which is causing the problem. For example, I just ran

SELECT Count() 
FROM LargeObject__c

and got the result back (5million) in <10 seconds. When I add on a WHERE clause

SELECT Count() 
FROM LargeObject__c
WHERE somefield > 1   //somefield is not an indexed field

it increased the time taken to 280 seconds. You could try raising a case with Salesforce and asking them to index your txt_State__c field, this might help with the performance and result in the query running in an acceptable length of time.